„Brainwash“ von Harald Eia („The Gender Equality Paradox“)

Gerade stark durch die Blogs gehen die Videos von Harald Eia, einem norwegischen Komiker und Soziologe, der in einer ernsten Reportage einiges zur menschlichen Natur darstellt und dabei insbesondere die Vertreter gesellschaftlicher Begründungen und die Vertreter biologischer Begründungen gegenüberstellt.

Es handelt sich um eine Beitragsreihe bestehend aus 7 Videos, die inzwischen auch bei Youtube zu finden sind:

1. Brainwash – The Gender Equality Paradox

2. Brainwash – The Parental Effect

3. Brainwash – Gay/Straight

4. Brainwash – Violence

5. Brainwash – Sex

6. Brainwash – Race

7. Brainwash – Nature or Nurture

Gerade das erste Video hat aus naheliegenden Gründen in den feminismuskritischen Kreisen einiges an Beachtung bekommen. Ich empfehle die anderen ebenso.

Zunächst einmal: Ich liebe den Klang des norwegischen. Es hat eine ganz eigene Melodie, eine Schwingung in dem Gesprochenen, die sich für mich sehr schön anhört.

Aber das nur nebenher: Interessant an dem ersten Video ist gerade, dass man merkt, dass die Forscher des Genderinstituts klassisch feministisch nur die eigenen Theorien für maßgeblich halten und sie nicht mit dem übrigen Forschungsstand abgeglichen haben. Sie sind erkennbar nicht auf Gegenargumente vorbereitet („TotalRej“ lässt grüßen) und kommen deswegen ins Stottern. Man merkt bei ihren Erwiderungen, dass sie bereits die Fragen für ein Verbrechen, für unwesentlich, für falsch halten, weil sie eben auf den falschen Weg führen, weg von der reinen Lehre und sie sich daher gar nicht erst mit ihnen beschäftigen wollen. Die Ideologie, dass alles gesellschaftlich begründet ist, ist aus ihrer Sicht unangreifbar wahr, und das lässt sie sehr schlecht aussehen, zumal mal eben mehrmals dabei erwischt werden, dass sie keine Ahnung haben, etwa wenn sie angeben, dass es keine Studien gibt, die eine biologische Sicht stützen oder ihre Antworten erkennen lassen, dass sie unabhängig von jeder Studie an ihrer Meinung festhalten werden und an die Sache nicht mehr objektiv herangehen können. Die übrigen Forscher wirken hingegen sachlich und abgeklärt.

Genial finde ich Eias Art, die Forscher zu befragen. Er nickt, er gibt Bestätigung, animiert sie zum weiterreden, schafft es, sie am reden zu halten. Andere wären vielleicht zu früh zu konfrontativ geworden und dann hätte man vielleicht die Antworten nicht so umfangreich bekommen.

Natürlich bleibt die Serie an der Oberfläche und ist in einigen Fällen sehr ungenau, etwa wenn er den Ausführungen der Genderwissenschaftler zum Umgang mit Kindern die Schilderungen seiner Mutter gegenüberstellt, die ja eher einen Einzelfallcharakter haben und bei denen man ein unterbewusstes geschlechtsbezogenes Behandeln nicht ausschließen kann. Die Qualität des Beitrages liegt aber darin, dass man einen subjektiven Eindruck erhält, wer die besseren Argumente hat, einfach, weil man die Reaktion der Genderforscher sieht, die keine Ahnung vom Thema haben und unsicher werden, obwohl eigentlich genau dies ihr Spezialgebiet ist, auf dem sie die entsprechenden weithin bekannten Studien gelesen haben sollten.

Der erste Beitrag soll in Norwegen zu starken Debatten geführt haben. Eine Folge soll die Streichung von Fördergeldern, wohl 56 Millionen Kronen, für das Gender Institut gewesen sein, was zu dessen Auflösung führte (hat jemand da eine Quelle zu?).

1. Wie findet ihr die Beiträge?
2. wenn ihr sie gut findet: Wie bekommt man sie ins deutsche Fernsehen?

Auswirkung postnataler Hormone auf das Gehirn

Eine Studie zu den Auswirkungen postnataler Hormone auf das Gehirn:

Objective: Sex hormones are not only involved in the formation of reproductive organs, but also induce sexually-dimorphic brain development and organization. Cross-sex hormone administration to transsexuals provides a unique possibility to study the effects of sex steroids on brain morphology in young adulthood.

Methods: Magnetic resonance brain images were made prior to, and during, cross-sex hormone treatment to study the influence of anti-androgen + estrogen treatment on brain morphology in eight young adult male-to-female transsexual human subjects and of androgen treatment in six female-to-male transsexuals.

Results: Compared with controls, anti-androgen + estrogen treatment decreased brain volumes of male-to-female subjects towards female proportions, while androgen treatment in female-to-male subjects increased total brain and hypothalamus volumes towards male proportions.

Conclusions: The findings suggest that, throughout life, gonadal hormones remain essential for maintaining aspects of sex-specific differences in the human brain.

Quelle: Changing your sex changes your brain: influences of testosterone and estrogen on adult human brain structure

Aus der Studie:

It is well established in mammals that differences in male and female brain structures can be reversed by sex hormones, even in adulthood (1). However, it is not known whether alterations in sex hormone levels can change structures of the human brain in adulthood. In human adults, the volumes of the brain and hypothalamus of males tend to be larger than those of females (2). The preoptic nucleus of the hypothalamus is even twice as large in males as in females (3). Moreover, in some studies, when comparing the fractions of gray and white matter in the brain, adult females as compared with males were found to have a higher fraction of gray matter, whereas adult males as compared with females had a higher fraction of white matter (4, 5).

Also bei Männern mehr graue Masse, bei Frauen mehr weiße Masse und bei Transsexuellen jeweils Veränderungen hin zu dem anderen Geschlecht hin

The changes in total brain and hypothalamus volumes following cross-sex hormone treatment in the transsexuals were mirrored by changes in their third and lateral ventricle volumes, i.e. treatment with estrogens and anti-androgens in MFs increased third and lateral ventricle volumes, whereas treatment with androgens decreased the third and lateral ventricle volumes in FMs. This suggests that the total brain volume changes are at least in part due to changes in medial brain structures surrounding these ventricles (including, but not limited to, the hypothalamus, which lies in close proximity to the third ventricle). Considering that the effects were not specific for gray (neurons, glia) or white (myelinated axonal fibers) matter suggests that both alterations in nerve cells as well as in axonal fibers may be implicated in the anatomical brain changes following cross-sex hormone treatment in humans. It is not surprising that the influences of sex hormones on the brain were not limited to the hypothalamus, but were also expressed as changes in total brain size. Estrogen and androgen receptor mRNA containing neurons are not limited to the hypothalamus, but are distributed throughout the adult human brain (18).

Es scheint also, als hätte postnatales Testosteron eine andere Auswirkung auf die Gehirnstruktur als pränatales. Gewisse Strukturen scheinen angleichbar zu sein, andere nicht.

Zwillinge und Homosexualität

Eine Studie dazu, welchen Anteil Umwelt bzw. Gene an Homosexualität haben anhand einer Zwillingsstudie:

There is still uncertainty about the relative importance of genes and environments on human sexual orientation. One reason is that previous studies employed selfselected, opportunistic, or small population-based samples. We used data from a truly population-based 2005–2006 survey of all adult twins (20–47 years) in Sweden to conduct the largest twin study of same-sex sexual behavior attempted so far. We performed biometric modeling with data on any and total number of lifetime same-sex sexual partners, respectively. The analyses were conducted separately by sex. Twin resemblancewas moderate for the 3,826 studied monozygotic and dizygotic same-sex twin pairs. Biometric modeling revealed that, in men, genetic effects explained .34–.39 of the variance, the shared environment .00, and the individualspecific environment .61–.66 of the variance.Corresponding estimates among women were .18–.19 for genetic factors, .16–.17 for shared environmental, and 64–.66 for unique environmental factors. Although wide confidence intervals suggest cautious interpretation, the results are consistent with moderate, primarily genetic, familial effects, and moderate to large effects of the nonshared environment (social and biological) on same-sex sexual behavior.

Quelle: Genetic and Environmental Effects on Same-sex Sexual Behavior: A Population Study of Twins in Sweden

Aus der weiteren Zusammenfassung:

It has been suggested that individual differences in heterosexual and homosexual behavior result from unique environmental factors such as prenatal exposure to sex hormones, progressive maternal immunization to sex-specific proteins, or neurodevelopmental instability (Rahman, 2005). Although the unique environmental variance component also includes measurement error, the present results support the notion that the individual-specific environment does indeed influence sexual preference. In conclusion, although confidence intervals were wide, we believe this study provides the most unbiased estimates presented so far of genetic and non-genetic contributions to same-sex sexual behavior. The results should inform further research on this complex trait

Und eine weiter Studie, die auf die Digit Ratio abstellt:

The 2nd to 4th digit ratio has been argued to reflect prenatal hormonal influences and is reportedly associated with various psychological and behavioral traits, such as sexual orientation, cognitive abilities, and personality. We examined genetic and environmental influences on the 2nd to 4th digit ratio (2D:4D) using a Japanese twin sample (N = 300). The genetic analysis showed substantial additive genetic influences for both right and left hand 2D:4D. The rest of the variance was explained mainly by environmental influences not shared within twin pairs. These findings were, in general, in accordance with preceding studies with primarily Caucasian twin samples. The bivariate genetic analysis revealed that the additive genetic influences were largely shared between the right and left hand, while the non-shared environmental influences were largely unique to each hand. Results from a comparison of opposite-sex and same-sex twins were not significant, although they were in the predicted direction according to the prenatal hormone transfer hypothesis. Female monozygotic twin pairs discordant in sexual orientation showed significant within-pair differences in left hand 2D:4D, where non-heterosexual twins had lower (more masculinized) 2D:4D. In addition, we found that non-heterosexual male MZ twins had larger (more feminized) 2D:4D than their heterosexual co-twins. These results suggest the existence of non-shared environmental influences that affect both 2D:4D and sexual orientation

Quelle: The Second to Fourth Digit Ratio (2D:4D) in a Japanese Twin Sample: Heritability, Prenatal Hormone Transfer, and Association with Sexual Orientation

Aus der Studie:

If the prenatal environment has some influence on 2D:4D, we would expect that even DZ co-twins are similar to each other because of the shared prenatal environment. The small shared environmental influences do not support the prediction. This suggests the possibility that twins do not share their prenatal hormonal environment. To test prenatal hormonal influences more directly, a second type of twin study compared twins from opposite-sex pairs (OS pairs) to those from same-sex pairs (SS pairs).(…) A recent meta-analysis showed that non-heterosexual females, including both homosexuals and bisexuals, had smaller (more masculine) 2D:4D than heterosexual females (Grimbos et al., 2010). Hall and Love (2003) conducted a within-pair comparison of 2D:4D of seven female MZ twin pairs with discordant sexual orientation. In each pair, one co-twin had a heterosexual orientation and the other had a homosexual orientation. In agreement with Grimbos et al.’s meta-analysis, Hall and Love reported that female homosexual MZ co-twins had more masculine 2D:4D compared with their heterosexual co-twins. A within-pair comparison of five female MZ twin pairs with concordant sexual orientation was not significant. Because MZ pairs share 100 percent of their genotypes, the differences between them must be explained by non-shared environmental influences. The environmental influences could include epigenetic effects. Previous results suggest that the same non-shared environmental factors that affect 2D:4D could also affect sexual orientation, indicating an overlap of environmental effect between the two phenotypes.

Dazu hatte ich auch bereits etwas in anderen Artikeln geschrieben:

• Vererbbare Faktoren in der sexuellen Orientierung bei Frauen
• Biologische Unterschiede zwischen Zwillingen

Die Studien zeigen, dass die Gene und die pränatalen Hormone Gründe für Homosexualität haben können und Unterschiede zwischen Zwillingen gerade in diesem Bereich bestehen.

Männliche Geschlechtsidentität und männliches Verhalten: Die Rolle von Sexhormonen in der Gehirnentwicklung

Ein Artikel (PDF) fasst einiges zu der Rolle von Hormonen und ihren Auswirkungen zusammen und geht dabei auch auf gesellschaftliche Faktoren ein.

Auch hier wird das bereits bekannte Modell dargestellt:

Apart from the sexual differentiation of the genitalia, sex hormones in the prenatal environment influence the differentiation of the brain into male or female. Pre- and early neonatal exposure of the brain to sex hormones leads to permanent changes in the nervous system. These effects are referred to as organizational effects. From vertebrate models we learn that the steroid hormone testosterone accounts for the majority of the known sex differences in neural structure and behavior. In lower animals, the presence or absence of testosterone at the time of a critical period of brain sexual differentiation influences the morphology of certain brain nuclei. Like its influence on the development of the genitalia, the presence of testosterone leads to male sexual differ en tiation of the brain and results in male-typical behavior, while a female brain and female-typical behavior are found to be the outcome of the absence of testosterone. When the testes are formed, they begin to produce testosterone and from this moment on there is a sex difference in testosterone concen trations between male and female fetuses. Through its effects on neurogenesis, cell migration, cell death, and the differentiation of neural circuits, testosterone has its effects on neuronal organization.

Also das klassische Modell der Formatierung des Gehirns durch pränatale Hormone.

Einige aus meiner Sicht ganz interessante Stellen aus dem Bericht:

Etwas zur Entwicklung der Geschlechterrollen bei Kindern:

With regard to the concept of gender, children first learn to identify their own and others’ sex (gender labeling). Next, they learn that gender is stable over time (gender stability). Finally, they learn that superficial changes in appearance or activities (a boy does not become a girl overnight if he puts on a wig or plays with Barbie dolls) does not change one’s gender. This is the last stage of gender constancy (gender consistency). This last phase is reached between 5–7 years, but long before that age, children appear to have knowledge about gender stereotypes (for an overview see Ruble et al. 2006).

Das ist erst einmal ein interessanter Überblick, der eben auch die Geschlechterrollen mit einfließen lässt. Es ist auch interessant in Bezug auf die Kinder mit Gendervarinanz und auch in Hinblick auf Steroid-5α-Reduktase-Mangel.

 Zu dem Spielverhalten von Kindern:

At very early ages children become interested in same-sex playmates. Boys like other boys better than girls and spend a fair amount of time in the company of other boys. Changing this peer preference appears to be difficult. Children thus spend an important part of their time in all-male or all-female groups. Boys tend to play in larger groups, play in more public places and with less proximity to adults, and play rougher and with more body contact. Boys fight more and their social interaction is oriented more toward issues of dominance. Girls’ groups are less hierarchically organized and their friendships are more intense. Girls appear to use language to create and maintain relationships, to criticize others in acceptable ways, and to interpret accurately the speech of other girls. In boys, speech is used to attract and maintain an audience, to assert one’s position of dominance, and to assert oneself when others have the floor. So gender segregation has far-reaching consequences for children’s social development and friendships.

Hier zeigen sich also die Unterschiede bereits bei den Kindern. Sie nehmen die Unterschiedlichkeit wahr und spielen deswegen lieber untereinander. Ich hatte dazu bereits einige Artikel:

• Lebensphasen und Geschlecht
• Hierarchien und Rangausbildung bei Jungen und Mädchen

Zur Aktivierung der vorformatierten Gehirne durch postnatale Hormone:

Later in life, neural circuits and behavioral patterns are activated by changing levels of sex hormones. An example of these so-called activating effects is the stimulation of the already sexually differentiated nervous system by gonadal hormones during puberty. Because steroid-dependent organization of brain and behavior also takes place during adolescence, it has been suggested that these activating effects should also be characterized as organizational effects. The timeframe for organi zational effects may not be limited to prenatal and early neonatal periods, but may also include puberty and adolescence. Steroid dependent organization during puberty implies that certain adult sex-typical behaviors are expressed because pubertal hormones first have organized neural circuits in the developing adolescent brain and that these circuits are subsequently activated by gonadal hormones

Dies wird in dem Artikel noch durch ein Beispiel erläutert.

Weitere Auswirkungen der postnatalen Hormone:

Other sex differences in brain and behavior in adulthood may also be related to the effects of sex hormones. Subcortically, in the hypothalamus, sex differences are observed in the interstitial nuclei of the anterior hypothalamus (INAH-1, INAH-2, INAH-3) and the central portion of the bed nucleus of the stria terminalis, with larger volumes in men than in women. These sex differences in the hypothalamus are thought to underlie sex differences in gender identity, reproduction, and sexual orientation. Gender-related cognitive functioning has been related to size and shape of the corpus callosum. Sex differences have been reported for the corpus callosum, but there is disagreement about the direction of the sex effect and some studies failed to detect such an effect. Men do show more morpho logical asymmetry than women and appear to have a somewhat more lateralized brain with left hemi sphere dominance for language processing and right hemisphere dominance for spatial processing. Regions with developmentally high densities of estrogen and ARs show greater sexual dimorphism. For example, the amygdala has a larger volume in males.

Auch das finde ich sehr interessant. Dort wo die Rezeptoren für Östrogene oder Testosterone dichter sind, zeigen sich auch mehr Unterschiede. Es ist bereits schwer zu erklären, warum unser Gehirn überhaupt diese Rezeptoren im Gehirn vorhanden sein sollen, wenn keine Geschlechtsunterschiede existieren sollen. Nur in einem Modell, wo je nach Stand der Geschlechtshormone unterschiedliche Ausprägungen des Gehirns erfolgen sollen, machen die Rezeptoren überhaupt Sinn.

Zu den Unterschieden in Krankheiten:

Sex differences in the amygdala’s response have been mentioned as factors to explain sex differences in the prevalence of psychiatric disorders. For instance, depression is less common in men than in women and is associated with sex differences in the role of the amygdala in emotional memory. Men and women also differ in the occurrence of other psychiatric disorders. Schizophrenia, attention deficit hyperactivity disorder, and autism primarily hamper men (for an overview see Bao & Swaab 2010), whereas eating- and anxiety disorders are more prevalent in women. Sex ratios for neuro logical disorders differ as well, with Rett syndrome (non-existent in men) and KleineLevin syndrome (non-existent in women) as extremes.

Und weiter zu Personlichkeits unterschieden:

Finally, personality characteristics also show sex differences. In general, physical aggression appears to be higher in men, whereas empathy has been found to be higher in women

Des weiteren geht der Artikel noch ein auf:

• Diethylstilbestrol (DES) in der Schwangerschaft: a synthetic estrogen that masculinizes and defeminizes brains and behavior in female rodents, have been found to show higher rates of homosexual imagery or homo sexuality than controls, but no masculine gender identity. Effects of exogenous hormones on male behavior and interests are less clear and often conflicting
• phenobarbital- and phenytoin in der Schwangerschaft: , it was found that the individuals as a group did not differ with respect to gender role behavior, but that higher numbers of prenatally exposed subjects reported current or past gender variant behavior and/or gender dysphoria. Gender dysphoria is the distress resulting from conflicting gender identity and gender of assignment. In a group of 147 subjects, there were also 3 transsexuals. This is a remarkably high rate given the rarity of transsexualism
• Congenital adrenal hyperplasia (CAH): These women, who are born with more or less virilized external genitalia, are generally treated early in life to normalize hormone levels and often undergo surgery to feminize Maggi_c01.indd 5 Maggi_c01.indd 5 10/15/2011 6:11:27 PM 10/15/2011 6:11:27 PM6 · Male gender identity and masculine behavior their genitalia. Girls with CAH generally show increased male-typical play behavior. Masculine gender role behavior also appears to be common in women with CAH across the lifespan. In women with CAH, a doseresponse correlation has been found; with the more seriously affected “salt-losing” women showing more masculine behavior than the less affected “simple-virilizing” women. In contrast, women with CAH, who were raised as females, mostly have feminine gender identities. However, these women show a less strong female identification, elevated levels of gender discomfort, and even gender dysphoria (∼5%) than non-DSD women.
• Gender development and 5a-reductase-2 deficiency (5a-RD-2) and 17b- hydroxysteroid dehydrogenase-3 deficiency (17b-HSD-3): Children with 5α-RD-2 have an enzyme defect that prenatally blocks the conversion of testosterone into dihydrotestosterone. Consequently they are born with external genitals that are female in appearance. They are usually raised as girls and seem to have a female gender identity, but, if the condition is not discovered in childhood, these children develop male sex characteristics in puberty: growth of their “clitoris” and scrotum, lowering of the voice, beard growth, masculine muscle development, and masculine body fat distribution. After puberty, many of these youngsters start living as males and develop a sexual attraction toward females
• Gender development and CAIS/PAIS: Individuals with complete androgen insensitivity syndrome (CAIS), who are raised as girls, are described as very feminine in their gender role behavior, although there may be more variability in their behavior than has long been assumed. They have a female gender identity and in the review by de Vries et al. (2007), none of the women with CAIS reported suffering from gender dysphoria or made a gender transition. But in the partial form of this condition, partial androgen insensitivity syndrome (PAIS), another picture emerges. In female-raised individuals, 11% were gender dysphoric or changed gender (5 of 46). In the male-raised group, this percentage was even higher, where 14% were gender dysphoric or changed gender (5 of 35).
• Gender development and ablatio penis: Der David Reimers Fall und ähnliche
• Transsexualität
  •  Post-mortem studies: Postmortem studies into the brain material of transsexuals revealed a sex reversal in volume and neuron number in the central portion of the bed nucleus of the stria terminalis and the interstitial nucleus 3 of the anterior hypothalamus in male-to-female transsexuals (MtFs) and a female-to-male (FtM) transsexual.
  • Luteinizing hormone (LH) regulation: Konnte die vermuteten Ergebnisse nicht erreichen
  • Cognitive studies: In studies examining IQ and verbal/spatial subtests, some samples of individuals with gender identity disorder (GID) show a pattern of cognitive functioning that is not in line with the natal sex. However, the results are too inconsistent to draw definite conclusions.
  • Handedness studies
  • Imaging studies: Magnetic Resonance Imaging (MRI) in untreated MtFs shows that their gray matter volumes are mostly consistent with men (their natal sex), but that the gray matter volume of the putamen was feminized. In addition, cerebral activation patterns in trans sexuals prior to treatment seem to share more features with those of the experienced gender than those of their natal sex. This was observed using Positron Emission Tomography (PET) during the processing of pheromones and using functional MRI while viewing erotic film excerpts. Finally, differences have been found within the cortical network engaged in mental rotation between MtFs (prior to as well as during hormonal treatment) and control males

Frau-zu-Mann-Transsexuelle und Autismus

Eine interessante Studie beschäftigt sich mit Frau-zu-Mann-Transsexuellen und Autismus:

The ‘extreme male brain’ theory suggests females with Autism Spectrum Conditions are hyper-masculinized in certain aspects of behavior. We predicted that females with Gender Identity Disorder (who are masculinized) would have elevated Autism Spectrum Quotient (AQ) scores. AQ scores from five groups were compared: (1) n = 61 transmen (female-to-male transsexual people); (2) n = 198 transwomen (male-to-female transsexual people); (3) n = 76 typical males; (4) n = 98 typical females; and (5) n = 125 individuals with Asperger Syndrome (AS). Transmen had a higher mean AQ than typical females, typical males and transwomen, but lower than individuals with AS. Transmen have more autistic traits and may have had difficulty socializing with female peers and thus found it easier to identify with male peer groups.

Quelle: Brief Report: Female-To-Male Transsexual People and Autistic Traits (PDF)

Das ist interessant, weil die Theorie des „extrem männlichen Gehirns“ Autismus als eben eine solche Ausprägung ansieht, weswegen Männer wesentlich häufiger von Autismus betroffen sind als Frauen. Nach dieser Theorie wären solche extrem männlichen Gehirne eher auf Sachen und weniger auf Personen bezogen, weswegen Autisten mit Menschen gar nicht zurecht kommen und ihre Handlungen wesentlich schwerer verstehen. Der Schluss daraus ist, dass Frauen mit einem solchen extrem männlichen Gehirn sich dann eben eher als Männer sehen und auf deren Art denken, zumindest auf diese Weise eher mit Männern zurechtkommen als mit Frauen.

Die Forscher dazu:

We found there was no difference between transwomen and control males on the AQ: transwomen have a mean AQ score that lies in the average range for both control males and females, and is not significantly different from either. Similarly, the proportion of transwomen with BAP and MAP also lies between control males and control females. Interestingly, within the 198 transwomen group, there were 6 individuals (i.e. 3%) with a diagnosis of AS. This rate is about 3 times as many as in the general population (Baird et al. 2006), although we have not calculated confidence intervals for this, it is consistent with previous studies (de Vries et al. 2010). Interestingly, among the transwomen sexual preference influenced AQ scores, consistent with findings that there are different typologies among transwomen based upon their sexual orientation (Lawrence 2010). Future research should explore this connection, as it appears that the association between GID and ASC in transwomen is complex

Aus der Besprechung am Ende:

In closing, this study provides evidence that transmen have an elevated number of autistic traits. This may be a reflection of elevated FT levels since both normative amniotic testosterone studies (Chapman et al. 2006; Knickmeyer et al. 2005) and studies of rare genetic conditions in which FT levels are abnormally high (such as in females with Congenital Adrenal Hyperplasia) (Knickmeyer et al. 2006a) indicate that higher FT is correlated with reduced empathy, reduced social interest, reduced social skills, and higher AQ scores. Quite how this is expressed in terms of neural masculinization (Baron-Cohen et al. 2005) is an important question for further study, which we are currently seeking to answer using MRI in children whose amniotic FT levels are known. The causation of GID and its development is complex and this paper is a contribution regarding a particular association between GID and ASC.

 

Wie beeinflussen sich verschiedengeschlechtliche Zwillinge im Mutterleib? (Twin testosterone transfer hypothesis)

Eine Hypothese ist, dass bei verschiedengeschlechtlichen Zwillingen gegenseitige hormonelle Beeinflussungen auftreten können. Insbesondere wird vermutet, dass der höhere Testosteronspiegel des männlichen Zwillings den weiblichen Zwilling beeinflusst. Wenn der weibliche Zwilling einem höheren Testosteron ausgesetzt ist, dann könnte das in den passenden Monaten Auswirkungen haben. Es ist aber in diesem Bereich noch vieles unklar:

Die Wikipedia hat folgendes dazu:

Prenatal Testosterone Transfer also known as prenatal androgen transfer or prenatal hormone transfer refers to the phenomenon in which testosterone synthesized by a developing male fetus transfers to one or more developing fetuses within the womb and influences development. This typically results in the partial masculinization of specific aspects of female behavior, cognition, and morphology,[1] though some studies have found that testosterone transfer can cause an exaggerated masculinization in males.[2] There is strong evidence supporting the occurrence of prenatal testosterone transfer in rodents and other litter-bearing species,[1] such as pigs.[3] When it comes to humans, studies comparing dizygotic opposite-sex and same-sex twins suggest the phenomenon may occur, though the results of these studies are often inconsistent.[4][5]

Der Mechanismus wird dort wie folgt dargestellt:

Testosterone is a steroid hormone; therefore it has the ability to diffuse through the amniotic fluid between fetuses.[6] In addition, hormones can transfer among fetuses through the mother’s bloodstream

Eine Studie dazu:

In this paper we review the evidence that fetuses gestated with a male co-twin are masculinized in development, perhaps due to the influence of prenatal androgens: the so-called twin testosterone transfer (TTT) hypothesis. Evidence from studies of behavioral, perceptual, cognitive, morphological and physiological traits in same- and opposite-sex human twins is considered. Apart from two studies reporting increases in aspects of sensation-seeking for females with a male rather than a female co-twin, there is sparse evidence supporting the TTT hypothesis in behavioral studies. Outcomes from studies of perception (in particular otoacoustic emissions) and cognition (in particular vocabulary acquisition and visuo-spatial ability) provide more consistent evidence in support of masculinized performance in twins with a male co-twin compared to twins with a female co-twin. The outcomes favorable to the TTT hypothesis for otoacoustic emissions and visuo-spatial ability are restricted to females. Studies of physiology and morphology (e.g., brain volume, tooth size and 2D:4D ratio) also show some influence of co-twin sex, but again these effects are often restricted to female twins. Because females produce little endogenous testosterone, the effects of gestation with a male co-twin may be more pronounced in females than males. Thus, while uneven, the evidence for the TTT hypothesis is sufficient to warrant further investigation, ideally using large samples of same- and opposite-sex twins, along with control groups of same- and opposite-sex siblings when the characteristics assessed are potentially open to social influences.

 

Highlights

► Hormones can transfer between fetuses in animals affecting phenotypic development. ► The existence of a similar mechanism in humans remains uncertain. ► A review finds little evidence for masculinization of behavior due to testosterone transfer. ► Some evidence consistent with transfer for perception, cognition and physiology. ► Evidence of masculinization is typically restricted to females with a male co-twin.

Quelle: Evaluating the twin testosterone transfer hypothesis: A review of the empirical evidence

Hier ist also noch vieles unklar. Es scheint einige Hinweise zu geben, dass der Mechanismus auch bei Menschen greift, aber es ist hier wohl weitere Forschung abzuwarten.

Hormone und sexuelle Orientierung

Eine gute Zusammenfassung zu dem Thema „Hormone und sexuelle Orientierung bietet der folgende Minireview:

Many people believe that sexual orientation (homosexuality vs. heterosexuality) is determined by education and social constraints. There are, however, a large number of studies indicating that prenatal factors have an important influence on this critical feature of human sexuality. Sexual orientation is a sexually differentiated trait (over 90% of men are attracted to women and vice versa). In animals and men, many sexually differentiated characteristics are organized during early life by sex steroids, and one can wonder whether the same mechanism also affects human sexual orientation. Two types of evidence support this notion. First, multiple sexually differentiated behavioral, physiological, or even morphological traits are significantly different in homosexual and heterosexual populations. Because some of these traits are known to be organized by prenatal steroids, including testosterone, these differences suggest that homosexual subjects were, on average, exposed to atypical endocrine conditions during development. Second, clinical conditions associated with significant endocrine changes during embryonic life often result in an increased incidence of homosexuality. It seems therefore that the prenatal endocrine environment has a significant influence on human sexual orientation but a large fraction of the variance in this behavioral characteristic remains unexplained to date. Genetic differences affecting behavior either in a direct manner or by changing embryonic hormone secretion or action may also be involved. How these biological prenatal factors interact with postnatal social factors to determine life-long sexual orientation remains to be determined.

Quelle: Minireview: Hormones and Human Sexual Orientation (PDF)

Er stellt zunächst verschiedene Modelle von Tieren und deren Erforschung dar, insbesondere Veränderungen in bestimmten Gehirnzentren unter dem Einfluss pränataler Hormone und deren Auswirkungen auf das Verhalten.

Zu der Übertragung auf den Menschen dann das Folgende:

Do these endocrine mechanisms demonstrated in animals have any significance in humans? The answer to this question should be considered in two steps. 1) Do we have any evidence that sex steroids are, in humans like in animals, implicated in the sexual differentiation of morphology (e.g. genital structures) but also of brain (e.g. SDN-POA) and sexual behavior? And 2) are there any data indicating that embryonic sex steroids have, like in animals, organizational effects on sexual orientation in humans? The answer to the first of these questions is clearly yes, and there is probably no need to elaborate on the arguments supporting this conclusion especially in an endocrine journal. To just briefly restate the obvious:

1) Sex steroids (testosterone, estradiol, progesterone) are present in the human plasma in concentrations similar to those observed in other mammals.

2) Receptors for these steroids are present in humans, and their brain distribution is similar and even nearly identical to the general pattern observed in vertebrates.

3) Testosterone action during embryonic life clearly controls the differentiation of male-typical external and internal genital structures.

4) Sex differences in brain structures have been identified, although their control by embryonic steroids is usually not established at this time.

5) Physiological or behavioral differences between men and women are too numerous to be summarized here (22). These differences are complex in nature, and their origin is more difficult to determine than for differences in genital morphology. Learning, education, and expectations of society clearly play an important role in the genesis of behavioral and even sometimes physiological differences. Nevertheless, quite often, these environmental factors build on and amplify smaller, sometimes minor, differences caused by biological factors that were already present at birth. Many physiological and behavioral differences are thus rooted in biology. This is quite obviously the case for many sexually differentiated diseases related to brain function (e.g. anorexia nervosa affects 93 women for every seven men; Gilles de la Tourette syndrome affects 90 men for every 10 women) (see Refs. 22–24 for an extensive list of such differences). How would education or society induce such differences? But many behavioral differences also probably depend to some extent on biological mechanisms often already acting during prenatal life (e.g. increased aggressivity and greater interest in male-typical activities in girls prenatally exposed to high androgen concentration due to congenital adrenal hyperplasia (CAH)

Es gibt also in der Tat viele Hinweise darauf, dass die gleichen Mechanismen, die auch bei den Tieren wirken, auch bei uns noch vorhanden sind. Ein Gedanke, der jedem Evolutionsbiologen auch recht nachvollziehbar erscheint. Gerade so grundlegende Funktionen wie etwa die Geschlechterdifferenzierung ist, gerade wenn auch ansonsten erkennbar viele körperliche Unterschiede zwischen den Geschlechtern bestehen, nicht einfach durch Evolution zu wandeln.

Und schließlich zur sexuellen Orientierung:

Sexual orientation is a sexually differentiated function that might depend, like many other behavioral characteristics, on variations in the early (fetal) exposure to sex steroids (androgens and also possibly their estrogenic metabolites). Exposure to a high concentration of testosterone during a critical phase of development would lead to a male-typical orientation (attraction to women), whereas a lower embryonic exposure to steroids would lead to a female-typical orientation (attraction to men). There would be a critical concentration of testosterone required to masculinize this feature like other aspects of behavior in animals and humans (see Fig. 2). On average, male embryos are exposed to higher concentrations of testosterone than female embryos, but these concentrations vary around a mean value for various reasons (environmental, genetic, etc.). Male subjects at the lower end of this sex-specific distribution could thus acquire a female-typical orientation (and be gay), whereas females at the high end of the concentration curve would acquire a male-typical sexual attraction and be lesbian. Even if they are not attracted by the same specific individuals, females and gay men share an attraction for men, whereas males and lesbians share an attraction for women.

Auch interessant ist ein Hinweis auf eine weitere Möglichkeit zu prüfen, welchem Testosteronstand die jeweilige Person pränatal ausgesetzt war:

Oto-acoustic emissions One set of studies also investigated the physiology of the inner ear and more specifically the small noises produced in the cochlea (presumably) by movements of the tympanic membrane, the so-called oto-acoustic emissions (OAE). OAE are produced either spontaneously or in response to short noises in the environment (e.g. clicks). These OAE are more frequent in women than in men as well as in females compared with males in a variety of animal species. In animals, OAE are masculinized (decrease in frequency) after embryonic treatment of females with androgens. OAE were shown to be significantly less frequent in lesbians compared with heterosexual women, again suggesting that these lesbians were exposed to higher concentrations of androgens than usual during early life. Similar studies assessing other aspects of acoustic physiology (e.g. auditory evoked potentials) that are also sexually differentiated confirmed a masculinization of these traits in lesbians (41). Interestingly, feminization of these features was never observed in gay men, and some studies even reported hypermasculinization of these traits

Klingt auf alle Fälle interessant und sollte man mal näher untersuchen. Das männliche Homosexuelle die Feminisierung nicht zeigen könnte drauf zurückzuführen sein, dass sie über dem „Schwellenwert“ liegen, während der Testosteronspiegel, der für Homosexualität bei Frauen ausreichend ist, eher unter dem liegt, der die Maskulinisierung in diesem Bereich bewirkt

Es werden dann noch unterschiedliche Gehirnstrukturen besprochen, desweiteren:

• 5
  -reductase deficiency: Ein Wechsel der Geschlechterrollen erfolgt mit der Pubertät unter dem Einfluss der Hormoen
• Congenital adrenal hyperplasia (CAH) : Wesentlich häufiger eine homosexuelle Orientierung, sind pränatal mehr Testosteron ausgesetzt
• Diethylstilbestrol (DES): Personen, deren Mütter während bestimmter Zeiten der Schwangerschaft mit DES behandelt wurden, wurden häufiger homosexuell
• Cloacal exstrophy:  Die Personen haben normale Hoden, so dass sie pränatalen Testosteron ausgesetzt sind, aber keinen Penis. Wurde bei der notwendigen Operation eine Geschlechtsumwandlung zu einer Frau durchgeführt, dann haben viele trotzdem später männliches Verhalten und ein sexuelles Interesse an Frauen gezeigt.

Zu den genetischen Komponenten:

Multiple epidemiological studies have demonstrated a correlation between concordance of sexual orientation and genetic relatedness. For example, if a boy is gay, between 20 and 25% of his brothers will share this sexual orientation, compared with 4 – 6% in a control population. Similarly, lesbian women have a greater probability than heterosexual women of having a homosexual sister. Twins studies indicate that this correspondence in sexual orientation probably does not reflect a communality of postnatal experiences (psychosocial factors) but rather genetic similarity. Several studies indeed demonstrated that there is a better agreement of sexual orientation in monozygotic (identical) twins than in dizygotic twins (fraternal twins conceived from different ova and sperm) (65). If a dizygotic gay twin has a brother, there is on average a 15% probability that the brother will also be homosexual, but this probability rises to 65% in monozygotic twins (66). Overall, these studies suggest that in social conditions typical ofWestern societies, 50 – 60% of the variance in sexual orientation in humans has a genetic origin.

Und auch interessant: Die Vererbung scheint eher über die mütterliche Linie zu erfolgen:

Sexual orientation in men tends to be transmitted through the matriarchal lineage: a gay man has a higher probability of having gay men among his ancestors on the maternal side (uncles, cousins), than on the paternal side. This was originally interpreted as a sign of inheritance through gene(s) located on the X chromosome, and one study identified a linkage with markers located in the subtelomeric region of the long arm of the X chromosome, a region called Xq28 (67). This association with Xq28 was replicated in one subsequent study (68) and in another set of data that were not published in a peer-reviewed journal (see Ref. 69) but not in a fourth one (70). A meta-analysis of all these data strongly supports (P
0.0001) the existence of this linkage (71). More recent studies have suggested that the differential heritage through the matriarchal lineage could also be the result of epigenetic modifications of the expression of genes located on several other chromosomes

Für die Gene der Mutter kann es auch vorteilhaft sein (im Sinne des egoistischen Gens) sehr fruchtbare Töchter zu erzeugen, auch wenn dies eine geringere Nachkommenzahl bei den Söhnen bedeutet. Mitochondriale DNA wird nur von der Mutter weitergeben, werden in dieser Veränderungen bewirkt, die im Zusammenspiel mit dem oben genannten Gen besonders fruchtbare Töchter produzieren, dann wird die mitochondriale DNA über diese schneller verbreitet und reichert sich damit im Genpool an. Der mitochondrialen DNA kann der Nachteil der homosexuellen Söhne egal sein, da diese sie eh nicht weiter verbreiten. Deren negative Auswirkungen führen nicht zu einer Selektion der mitochondrialen DNA.

Desweiteren geht er noch auf den Fraternal Birth Order effect ein, also den Umstand, dass Männer mit vielen älteren Brüdern eher homosexuell sind.

Ich finde es gibt eine gute Übersicht und empfehle den Beitrag zu lesen.

Weiteres zur Homosexualität auf diesem Blog:

• Biologische Gründe für Homosexualität
• Biologische vs. gesellschaftliche Begründung: Welche Theorie ist günstiger für Homosexuelle,Transsexuelle etc
•  Warum die sexuelle Identität biologisch sein muss
• Nochmal: Schönheit, Attraktivität und Evolution

Fähigkeiten in Verbindung mit den Hormonen (Östrogen / Testosteron)

Helen Fisher et al in einer Studie zu den verschiedenen Fähigkeiten und ihren Zusammenhängen mit den Hormonen:

In a meta-analysis of 150,000 Americans aged 13–22, those whose scores fell in the top 5–10% in math, geometry, mechanical reasoning and engineering were overwhelmingly male (e.g., Hyde, Fennema, & Lamon, 1990). Questionnaire studies in several other countries yielded similar results (e.g., Mann, Sasanuma, Sakuma, & Masaki, 1990). Most young adult men express approximately eight to ten times more testosterone than most women; and it is widely hypothesized that this sex difference in hormone expression contributes to the above sex differences in cognition. Although adult sex differences in cognitive tasks are not suffi- cient evidence for hormonal effects, biological data support this hypothesized correlation. The brain architecture associated with these spatial/mathematical skills has been associated with fetal testosterone (e.g., Geschwind & Galaburda, 1985; Grimshaw, 1995); and bodily levels of testosterone also contribute to spatial/mathematical dexterity across the life span (Janowsky et al., 1994). Further, it has been proposed that greater understanding of spatial, mechanical, mathematical, engineering and other rulebased systems is the result of more short-range and less long-distance neural connectivity, due to the exposure to prenatal androgens (e.g., Manning, 2002). Other traits that may be linked with prenatal testosterone expression are heightened attention to detail, intensified focus, and restricted (narrow) interests (e.g., Baron-Cohen, Knickmeyer, & Belmonte, 2005; Knickmeyer, Baron-Cohen, Raggatt, & Taylor, 2005); and elevated adult levels of testosterone have also been associated with these traits (Dabbs & Dabbs, 2000). It has been suggested that prenatal testosterone expression is also linked with less emotion recognition, eye contact and social sensitivity (e.g., Baron-Cohen et al., 2005), a poorer ability to judge what others are thinking or feeling (Baron-Cohen, 1995); and lack of empathy (Baron-Cohen et al., 2005). Adult expression of testosterone has been correlated with being less polite, respectful, considerate or friendly (Dabbs, 1997; Harris, Rushton, Hampson, & Jackson, 1996); and being more confident, forthright and bold (Nyborg, 1994). Adult levels of testosterone have also been positively correlated with sensitivity to social dominance, drive for rank, the tendency to create dominance hierarchies (e.g., Mazur, Susman, & Edelbrock, 1997), and aggressiveness (e.g., Dabbs, 1990; Mazur et al., 1997). Poor verbal fluency and other language deficiencies have been associated with testosterone priming in the womb (e.g., Baron-Cohen et al., 2005; Knickmeyer, Baron-Cohen, Raggatt, Taylor, & Hackett, 2006; Knickmeyer et al., 2005; Geschwind & Galaburda, 1985; Manning, 2002). Last, a lower (masculinized) second to fourth digit ratio has been associated with high prenatal testosterone (Manning, 2002). Women excel at several linguistic skills in US populations (e.g., Halpern, 1992; McGuinness & Pribram, 1979) and other countries (Mann et al., 1990). Cross-culturally, women also excel at recognizing emotions in faces (e.g., Hall, 1984; McClure, 2000), reading a person’s emotions from voice, gestures and other non-verbal cues (e.g., Hall, 1984; McGuinness & Pribram, 1979) and interpreting a range of mental states (Baron-Cohen, Jolliffe, Mortimore, & Robertson, 1997). Although these sex differences are not sufficient evidence for hormonal effects, studies suggest that nurturance and other prosocial skills are associated with adolescent and adult estrogen activities in human females (Nyborg, 1994) and females of many other mammalian species (Carlson, 2001). Adult estrogen facilitates memory for emotional experiences (Canli, Desmond, Zhoa, & Gabrieli, 2002). Estrogen replacement therapy increases verbal memory (Hogervorst, Williams, Budge, Riedel, & Jolles, 2000). In addition, estrogen receptor modulators can elevate adult working and episodic memory, executive function and verbal skills (Goekoop et al., 2005). Data suggest that fetal steroids affect several adult behaviors (Manning et al., 2000; Nyborg, 1994). Data also suggest that a higher (feminized) digit ratio is positively correlated with fetal estrogen (Manning, 2002). At present, however, there is insufficient evidence that fetal testosterone enhances the growth of the 4th digit or that fetal estrogen facilitates the growth of the 2nd digit.

Gleichmacherei im Feminismus?

Joachim meint, dass dem Feminismus Unrecht getan wird:

„Wann immer das Gespräch auf Gleichstellung, Feminismus, oder auch nur Kritik an offensichtlichen Sexismus kommt, wirft jemand dem Feminismus pauschal Gleichmacherei vor. (…) Aber der Vorwurf einer Gleichmacherei der Geschlechter steht im Raum. Und überrascht mich. (…)

Als ich erstmals von Queer-Feminismus und Genderstudies hörte und las, war ich begeistert, wie viel Freiheit diese Ansätze den Menschen bringen.

Die Reproduktion von Genderrollen ist keine Freiheit. Es gibt ja nur zwei klassische Geschlechterrollen, die zudem noch fest mit dem körperlichen Geschlecht verbunden sind. Deshalb ist die Aufweichung oder Auflösung dieser Geschlechterrollen keine Gleichmacherei sondern Befreiung. Thema der meisten FeministInnen (jedenfalls derer, die ich kenne) ist nicht die Zusammenführung der Genderrollen zu einer einzigen. Es geht vielmehr um Gleichstellung und Auflösung männlicher Privilegien. Es geht also darum, allen Menschen die gleichen Chancen zu geben. Dadurch werden sie nicht gleichgemacht.

Ich habe schon bei Joachim etwas diskutiert, aber da dort recht schnell Kommentare nicht mehr freigeschaltet werden, wenn sie Joachim nicht gefallen, lohnt es sich dort nicht so.

Meiner Meinung nach ist das Argument bereits nicht sehr schlüssig. Nur weil etwas Befreiung von einer Geschlechterrolle sein soll, schießt das nicht aus, dass man Leute gleich oder zumindest gleicher machen soll.

Das Problem ist aus meiner Sicht, dass die Grundeinstellung zwar ist, dass jeder frei ist und leben können soll wie er will, gleichzeitig aber bestimmte Rollen stark negativ besetzt sind, eben als Privilegiennutzung, Mackerverhalten, hegemoniale Männlichkeit oder Schlicht als Verhalten, welches Geschlechterrollen reproduziert.

Wenn bereits ein rosa Überraschungsei eine nicht hinzunehmende Reproduktion von Geschlechterrollen ist, dann kann jedenfalls für Leute, die diese Leben wollen, nicht von einem mehr an Freiheit gesprochen werden. Wenn männliches Verhalten abgewertet wird, dann kann auch nicht davon gesprochen werden, dass dies mehr Freiheit gibt.

Letztendlich scheint mir der Weg des Aufbrechens der Geschlechterrollen nur erreichbar zu sein, wenn eine gewisse Gleichmacherei weg von Geschlechterrollen erfolgt. Das Ziel ist insoweit ein ungeschlechtliches Verhalten oder zumindest eine starke Reflexion und ein begleitendes „Ich könnte mich auch jederzeit neutral verhalten, aber ich wähle jetzt gerade mal ganz bewusst und in Kenntnis der Hintergründe ein vermeintlich geschlechtliches Verhalten“.

Die Auflösung von Zwang ist sicherlich ein richtiger Weg, was ja aus meiner Sicht direkt aus den biologischen Theorien folgt. Wenn bestimmte Menschen im Gehirngeschlecht abweichend von ihrem Phänotyp sind, dann wäre es falsch sie in Geschlechterrollen einzuordnen. Er würde innerhalb der biologischen Theorien eh nichts bringen. Es gäbe dann nur keine gesellschaftlichen Geschlechterrollen (bzw. es gäbe nur kulturelle Ausprägungen der biologischen Dispositionen). Wer jemanden befreit, der nicht befreit werden möchte und nicht befreit werden kann, der unterdrückt.

Die Mittel der Befreiung gefallen mir hier auch nicht. Es mag sein, dass dieser Teil des Feminismus letztendlich Freiheit erreichen möchte, aber um die Geschlechterrollen aufzuheben will er ja die bisherigen Geschlechternormen mehr oder weniger radikal sabotieren. Da nach den dortigen Auffassungen solche gesellschaftlichen Vorgaben dadurch wirken, dass Leute sich auf eine bestimmte Weise verhalten, muss das breite Verhalten der Menschen geändert werden, damit die Normen an Wirkung verlieren.

Wer gesellschaftliche Normen verändern will muss zunächst ihre Ursprünge erforschen. Er sollte dabei nicht dabei stehen bleiben, was er mag, sondern von sich abstrahieren und nicht so egoistisch sein, lediglich eine Welt zu formen, in der er sich wohl fühlt, sondern eben bedenken, dass der Mensch nicht gleich ist, sondern höchst verschieden. Andere Menschen mögen andere Vorstellungen davon haben, wie man lebt. Der Versuch, ihren Vorstellungen aufgrund der eigenen Wahrnehmung die Richtigkeit abzusprechen, ist gefährlich.

Hier sollte man doch einmal die in der Wissenschaft aufgestellten Theorien und Studien werten, und nicht nur die Ergebnisse von wissenschaftsfeindlichen Poststrukturalisten wahrnehmen, die einer strikten Ideologie folgen, die kein anderes Ergebnis als die Gleichheit und kulturelle Prägung im Sinne eines Blank Slate zulässt.

Würden wir bei solcher Umerziehung über Tiere reden, etwa Bonobos zu sittsamen Verhalten erziehen wollen oder Schimpansen zu Hippies oder eben Gorillas zur Monogamie, dann wäre das ein unmenschliches Unterfangen, auch wenn die Ziele je nach politischer Ausrichtung als gut angesehen werden könnten. Wir Menschen sind auch Primaten. Das sollte man nicht einfach ausblenden

Die Auflösung von Geschlechterrollen kann natürlich insofern bUnterdrückung sein. Wenn die Häufungen eben aus biologischen Gründen vorhanden sind, dann ist es nicht weniger falsch jemanden aus der von ihm gewünschten Geschlechterrolle herauszubringen (um diese gesellschaftlich auflösen zu können) als etwa einen weiblichen Schwulen auf die Militärakademie zu schicken, damit er „männlicher“ wird.

Ich denke es wird unterschätzt wie viel Freiheit moderne biologische Theorien dem Menschen lassen. Denn es geht ja nicht mehr um einen binären Ansatz, sondern lediglich um Häufungen. Es gibt jedes Spektrum menschlichen Verhaltens eben auch in diesen Theorien, den sehr weichen Mann, die sie männliche Frau, den männlichen Schwulen und den eher weiblichen Schwulen, den Bisexuellen etc.

Sie alle sind zwangsläufig wie sie sind, weswegen eine Umerziehung, eine Formung des Menschen hin zu einem Rollenbild nicht sinnvoll ist.

Jeder Mensch hat insofern die individuelle Freiheit so zu sein, wie er ist.

Im Gegensatz zum konstruktivistischen Ansatz gibt es insofern zwar Häufungen, aber keine Umerziehung.

 

 

 

Tomboys

Dr. Mutti ist – wenn ich ihre bisherigen Beiträge richtig einordne – eine strikte Vertreterin sozial konstruierter Geschlechterrollen. In einem Artikel nimmt sie eine Studie über Tomboys, also Mädchen mit einem eher männlichen Verhalten unter die Lupe. Dabei ging es ihr inbesondere um den folgenden Satz in einem Artikel:

A 1998 study in the academic journal Sex Roles suggests just how ordinary it has become for girls to exist in the middle space: it found that 46 percent of senior citizens, 69 percent of baby boomers and 77 percent of Gen-X women reported having been tomboys.

Dem zugrunde liegt die folgende Studie:

The perceptions and definitions of tomboybehavior were explored across three generations ofwomen. The sample included 521 women (primarilyundergraduates, their mothers, and their grandmothers)ranging in age from 17 to 94 who were categorized intoone of three cohorts (Generation Xers, Baby Boomers orSenior Citizens) for a final sample of 466. The samplewas 87% European American, 6% Native American, 3% Hispanic, and 2% Asian American. Sixty-sevenpercent of the sample reported being tomboys duringtheir childhood. The average age reported for startingtomboy behavior was 5.8, whereas the average age for ceasing tomboy behavior was 12.6. Agecohort analyses revealed relatively few differences butseveral interesting findings. The senior citizens tendedto differ from both sets of younger women. For instance, senior citizens were less likely toreport being tomboys than were Xers or Boomers.Directions for future research include monitoring thesocial acceptability of tomboy behavior, assessingpotential cultural differences in tomboyism, andanalyzing correlates of the average age that tomboyismceases.

Quelle: A Three Generational Study of Tomboy Behavior (PDF)

Aus der Studie folgert sie:

Hier wird sehr deutlich, dass tatsächlich ein beträchtlicher Teil aller Mädchen sich zumindest nicht ausschließlich wie stereotype Mädchen verhalten – und das trotz der gesellschaftlichen Normvorstellungen. Das “Jungenverhalten” – oder sollten wir es vielleicht lieber als “normales Kinderverhalten bezeichnen? – wurde im Übrigen in den meisten Fällen ungefähr im Alter zwischen 12 und 13 Jahren abgelegt, also mit dem Einsetzen der Pubertät. Die meisten gaben Gruppendruck und wachsendes Interesse an Jungen (als Sexualpartner, nicht als Spielkameraden) als Grund für diese Veränderung an.

Also eine klassische soziale Begründung.

Meiner Meinung nach hat die Studie mehrere Fehler.

• Sie gibt keinen Maßstab vor, anhand dessen die Befragten ihre Tomboy-Aktivitäten bewerten können. Es bleibt also unklar, ob die Befragten meinten, dass sie für ein Mädchen häufig ein bestimmtes Verhalten zeigten und wie ihre Wahrnehmung insoweit ist. Auch bleibt der Intensitätsgrad zB bei Rough and Tumble Play unhinterfragt
• Eine Befragung über Fragebögen lädt zu einem Response bias ein (dazu auch S. 798)
• Es würde mich interessieren, aus welchen Studiengängen die Studentinnen kamen.
• Die erzwungene Wahl (Tomboy, ja oder nein) scheint mir auch ungünstig zu sein. Besser wäre es aus meiner Sicht erst das Verhalten abzufragen und daraus Schlüsse zu ziehen.

Vieles spricht dafür, dass tatsächliche Tomboys einen biologischen Hintergrund haben. Hier eine andere Studie dazu:

Levels of testosterone (T) and sex hormone–binding globulin (SHBG) were measured in blood samples from pregnant women and related to gender role behavior in 342 male and 337 female offspring at the age of 3.5 years. Gender role behavior was assessed using the Pre–School Activities Inventory, a standardized measure on which a parent indicates the child’s involvement with sex–typical toys, games, and activities. Levels of T, but not SHBG, related linearly to gender role behavior in preschool girls. Neither hormone related to gender role behavior in boys. Other factors, including the presence of older brothers or sisters in the home, parental adherence to traditional sex roles, the presence of a male partner in the home, and maternal education, did not relate to gender role behavior in this sample and did not account for the relation observed between T and behavior. Although other, unmeasured factors may explain the relation, the results suggest that normal variability in T levels prenatally may contribute to the development of individual differences in the gender role behavior of preschool girls.

Quelle: Testosterone during Pregnancy and Gender Role Behavior of Preschool Children: A Longitudinal, Population Study

Interessant ist ihre Erklärung dafür, dass sich bei Männern weniger Unterschiede zeigen:

„Compared to girls, boys are more strongly encouraged to behave in sex-typical ways and are more strongly discouraged from engaging in cross-gendered behavior,“ they write. „Thus, girls may be more likely than boys to manifest hormone-related predispositions to gender-role behaviors more characteristic of the other sex, because these predispositions are less likely to be counteracted by other influences.“

Also Frauen hätten danach mehr Freiheiten als Männer, was die Geschlechterrollen angeht.

Auch interessant: Eine Abgrenzung zwischen Tomboys und Homosexualität:

Being a tomboy may sometimes lead to being called a lesbian, a label that can carry a stigma among adolescents. Whether there is any real link to homosexuality depends on how you define tomboyism, says Carr. Tomboys who see their stance as a „rejection of femininity“ are more likely to be lesbians. Those who conceive of it as „choosing masculinity“—in dress, activity, and identification with male figures and heroes—are no more likely to to be gay than straight. Though lesbians are more likely to recall childhood gender nonconformity, almost half of women report having been tomboys as children, says Carr.

Aus dem gleichen Artikel fand ich auch die folgende Stelle interessant:

Hines also showed that tomboys are more likely to have brothers and parents who exhibit highly masculine behavior.

Was vielleicht deutlich macht, warum sich diese Variante genetisch lohnt. Es ist evtl eine Optimierung der Söhne zulasten der Töchter (auf deren Fruchtbarkeit bezogen) wie sie auch bei Homosexualität und in anderen Bereichen diskutiert wird.

Eine weitere Studie von Hines beleuchtet die Rolle der Hormone weiter:

Gonadal hormones, particularly androgens, direct certain aspects of brain development and exert permanent influences on sex-typical behavior in nonhuman mammals. Androgens also influence human behavioral development, with the most convincing evidence coming from studies of sex-typical play. Girls exposed to unusually high levels of androgens prenatally, because they have the genetic disorder, congenital adrenal hyperplasia (CAH), show increased preferences for toys and activities usually preferred by boys, and for male playmates, and decreased preferences for toys and activities usually preferred by girls. Normal variability in androgen prenatally also has been related to subsequent sex-typed play behavior in girls, and nonhuman primates have been observed to show sex-typed preferences for human toys. These findings suggest that androgen during early development influences childhood play behavior in humans at least in part by altering brain development.

Quelle: Sex Steroids and Human Behavior: Prenatal Androgen Exposure and Sex-Typical Play Behavior in Children

DrMutti zieht aus dem ganzen übrigens den folgenden Schluß:

die Studie selber erwähnt außerdem, dass die ehemaligen “Tomboys” erfolgreicher und selbstbewusster in ihrem späteren Leben waren und auch als ältere Menschen sich stärker sportlich betätigten. Also: Nicht-stereotypes Verhalten ist zumindest für Mädchen und Frauen einfach gesünder.

Dabei verkennt sie meiner Meinung nach, dass ein höheres Interesse an Wettbewerb, höheres Selbstbewußtsein und gute sportliche Fähigkeiten alle auf Testosteron zurückführbar sind. Es ist nicht so, dass nicht-stereotypes Verhalten hier gesünder ist, sondern, dass die Mädchen, die sich als Tomboys wohlfühlen besser als solche Leben sollten, die, die sich hingegen in den Geschlechterrollen wohl fühlen, besser innerhalb dieser leben.