The BBC has kind of an interesting quiz on sex and brains. But it's not all brains. They have you measure the length of your index finger verses your ring finger. Many of you have probably heard that heterosexual women tend to have index fingers the same length as their ring fingers, or longer, whereas straight men and lesbians tend to have longer ring fingers. Women also have better hearing than men, but lesbians do not hear as well as straight women and are more like men. etc etc etc blah blah blah
The BBC says that finger length ratios are set in the womb. The presence of pre-natal hormones sets primary and secondary sex traits, such as finger lengths, certain brain structures, all the other secondary sex traits that are present at birth and also genitals. I read recently that 4% of the population is born intersexed. That's a lot. Of course, this varies from slightly outside of "normal" to right in the middle. It seems like most IS people are not out. But it's also the case that most are simply not informed. Their genitals are "corrected" shortly after birth and they go on to live their lives. (Doctors will operate on genitals with greater urgency than on actual health issues. A baby with a heart defect has to wait, but a baby with weird gonads goes under the knife. It's a social emergency.) What's more is that doctors, for many years, didn't even bother to inform the parents. Nobody knows but the obstetrician.
It's true that the number of girls born every year is climbing. This is often explained by women waiting to start having kids. Younger mothers are somewhat more likely to have boys. Older mothers are somewhat more likely to have girls.
The number of queers also seems to be rising. This is often explained by a greater ease of being out. This definitely plays a part. The number of trans people is also growing, often attributed in the same way. Nobody knows how many trans people there are, but in She's Not There, Jennifer Finney Boylan asserts that the number of people who have had the surgery (she doesn't specify, but I assume she means bottom surgery for mtfs) in the US is greater than the number of people diagnosed with MS. That's a lot of people.
I've read that 80% of the fish in the San Francisco bay are female. This is blamed on pollution. I've heard people say that it's run off from birth control pills. Women take the hormones and then later pee them out. They are in the sewage system and eventually end up in the bay where they change the hormonal balances of pre-hatched fish eggs. Fish that would have been born male are instead born female.
If runoff is getting into fish, it's also getting into people. A lot of dangerous pesticides are something called "endocrine disrupters." The mimic chemicals that naturally occur in the endocrine system in people. They aren't so bad for adults, but they can really mess up a fetus. We have a kajillion scary chemicals all around us, as fire prevention treatment in our appliances, sprayed onto our food and just as environmental background. Many of these chemicals are similar to chemicals that naturally occur in our bodies.
Maybe the number of girls born every year has more to do with the number of female fish.
(Are there fish with gender confusion swimming around the bay?)
Autopsies of male to female transexuals show that their brains have structures more similar to female brains than to male brains. (I'm sorry, you'll have to google the source for this, I'm too lazy.) The researcher claims that these differences were not caused by hormones taken later in life. They instead were the result of hormones in the womb before those folks were born.
On the one hand, the right wing wants to crush queers and oppress us. On the other hand, there are more of us every year. they also want to spew pollution everywhere. But this may be inflating our numbers beyond what they might have been otherwise. I don't want to imply that being queer is any sort of birth defect, because I think it's an improvement. I think we ought to figure out which chemicals cause queers but don't cause any problems and use more of them and ban everything else.
(According to the BBC, I score just like an average woman, according to the summary. But if you look at the individual scores, I'm really, really good at "female" tasks and average male for "male" tasks. And my ring finger is unusually long for a man. Cola, however got more male than female. heh.)