Genes don’t cause every disorder or illness. When a baby is being formed, the conditions in the uterus definitely have an effect on development. Almost as much as the genes do. The study of epigenetics is all over this. The most easy to see and famous of the classic epigenetics studies is the one with the ponies and the horses. Pony embryos were implanted into the uteri of horses. The resulting ponies, 100% genetic ponies, were significantly LARGER than ponies.
So Darwin was correct but so was the much maligned Lamarck.
A lot of these gender or sexuality problems seem to stem from changes in the uterus. One study shows that homosexual men tend to have had older genetic brothers. Sometimes multiple. If someone has a few sons, the later ones would tend to be the gay ones.
Once again, this is not “chemical” anything.
This is a case of idiotic parents.
But hey, we are all free to be transracial, transexual, transpecies, and apparently transcomestible too.
MY GENES MADE ME DO IT ! - Chapter 7. Pre-natal hormones? Stress? Immune attack?
Although there are some pre-natal hormonal effects on sexual behaviour for lower animals, there is not con vincing evidence for such an effect on sexual orientation in humans. The studies examining the effects of high doses of female hormones to pregnant women are particularly informative because these are very high doses and any hormonal effects on sexual orientation should show up clearly. But the result is a dubious effect on women and no effects on men. Any effects on sexual orientation appear to be better explained in terms of gender non-conformity—a psychological construct. Sex hormones do increase or lower sex drive, but that appears to be about all.
The maternal immune hypothesis seems very speculative, and needs much more evidence before it is taken more seriously. We leave the last word to several researchers in the field. James summarises the evidence for effects of prenatal hormone exposure on subsequent sexual orientation as “weak”.
In summary, the evidence from prenatal endocrine disorders and from the offspring of hormone-treated pregnancies suggests that hormones may contribute to, but do not actually determine, the course of sexual orientation in individuals with an abnormal sex steroid history during prenatal life.
“At this time, the literature does not support a causal link between hormones and homosexuality.”
Also, “In clinical practice numerous patients are encountered with gross abnormalities of their hormonal profiles. As a rule this does not impact on their gender identity or sexual orientation.”