AIS, CAH, Sequential Hermpaphroditism, & Reciprocal Copulation

This is a great short article on the ambiguities of sex as expressed by humans, mammals, fish and various other creatures, and covers topics like chromosomal variety, embryonic sex determination, and reproductive strategies. It’s a nice Sex 101 – and by that I don’t mean sex as in f*cking, but sex as in male/female. A lot of reasonably smart and educated people seem to think that gender is variable but sex is “natural” and binary when in fact that’s not nearly as true either.

You’ve had your turkey. Now get your learning back on.

ATM Blog

Just discovered the blog American Trans Man, which, according to its description, is:

written by a FTM trans scientist who supplies information about different biological and genetic aspects of being transgender with a focus on the transmasculine.

I’m especially pleased there’s a focus on trans science.

One Gene Away

I’m not going to try to re-phrase this article about how ovaries/testicles are determined by a single gene. Better you read it from the source:

As embryos, our gonads aren’t specific to either gender. Their default course is a female one, but they can be diverted through the action of a gene called SRY that sits on the Y chromosome. SRY activates another gene called Sox9, which sets off a chain reaction of flicked genetic switches. The result is that premature gonads develop into testes. Without SRY or Sox9, you get ovaries instead.

But Henriette Uhlenhaut from the European Molecular Biology Laboratory has found that this story is woefully incomplete. Maleness isn’t just forced onto developing gonads by the actions of SRY – it’s permanently kept at bay by another gene called FOXL2.

Uhlenhaut developed a strain of genetically engineered mice, whose copies of FOXL2 could be deleted with the drug tamoxifen. When she did this, she found that the females’ ovaries turned into testes within just three weeks. The change was a thorough one; the altered organs were testes right down to the structure of their cells and their portfolio of active genes. They developed testosterone-secreting Leydig cells, which pumped out as much of the hormone as their counterparts in XY mice. They only fell short of actually producing sperm.

Uhlenhaut found that FOXL2 and SOX9 are mutually exclusive – when one is active, the other is silent and vice versa. The two genes are at opposite ends of a tug-of-war, with sex as the prize. FOXL2 sticks to a stretch of DNA called TESCO, which controls the activity of Sox9. By sticking to TESCO, FOXL2 keeps Sox9 turned off in the adult ovary. Without its repressive hand, Sox9 switches on and sets about its gender-bending antics.


Uhlenhaut’s work isn’t just of academic interest. It could also help to treat disorders of sexual development. It could also change how gender reassignment therapies are done, paving the way for gene therapies rather than multiple painful surgeries.

Emphasis mine. That is such a goddamned cool idea.

Tierney (un)Truth and (not) Dare

A little more than a week ago, John Tierney published an article in the NYT “daring” to question whether or not girls just aren’t good at math. What a goddamn revelation. I don’t know what we would do without such daring journalism.

Maggie Koerth-Baker over at BoingBoing actually interviewed some female scientists on the topic. One of them, a Dr. Isis, had some great things to say:

John Tierney titles his article “Daring to Discuss Women’s Potential in Science,” as though he is bravely daring to out the dirty little secret that we all supposedly know deep in our hearts. Girls suck at math and science. The truth is, they really don’t. It’s just that John Tierney sucks at googling.

I love the idea of John Tierney publishing pie recipes instead:

Yet, he clearly has ignored the fact that this phenomenon is unique to the United States. Indeed, in countries with more gender equal cultural norms, the divide disappears. In Iceland, girls out perform boys in math and science. Japanese girls out perform American boys. Maybe in his next column Tierney will argue some type of evolutionary difference between the boys and girls in these other countries and American boys and girls. Personally, I would find it much more interesting if he would start posting recipes for pies we could make with all the cherries he’s picking.

and then:

Can we all agree that Tierny pulled this completely out of his ass? Someone who scores in the top 99.9% of an aptitude test is more likely to get tenure than someone who scores in the top 99.1% in the seventh grade? Really?

Honestly, the NYT had no business publishing a poorly-researched and obviously biased article. Let’s all keep in mind that Tierney has already written in defense of Summers, which indicates some pre-existing bias — other than the obvious sexist one, of course.

These guys tire me.

Sex Difference Studies Suspect

Kudos to Scientific American and Lise Eliot – who published & wrote an article on sex brain difference studies, particularly the ones involving emotional sensitivity & the SG size in brains.

However, in both studies, Wood and colleagues added another test that reminds us to be cautious when interpreting any finding about sex differences in the brain. Instead of simply dividing their subjects by biological sex, they also gave each subject a test of psychological “gender:” a questionnaire that assesses each person’s degree of masculinity vs. femininity—regardless of their biological sex—based on their interests, abilities and personality type. And in both adults and children, this measure of “gender” also correlated with SG size, albeit in just as complicated a way as the correlation between “sex” and SG size. (Larger SG correlated with more feminine personality in adults but less feminine personality in children.)

In other words, there does seem to be a relationship between SG size and social perception, but it is not a simple male-female difference. Rather, the SG appears to reflect a person’s “femininity” better than one’s biological sex: women who are relatively less feminine show a correspondingly smaller SG compared to women who are more feminine, and ditto for men.

This article is some of the best writing on science & sex difference I’ve read – especially for lay folks who don’t want to tackle the work of someone like Fausto-Sterling.

It happens so rarely, but it’s so lovely when it does.