OK, this is just weird. A ridiculously common parasite can change people’s behavior, making us dumber and more sexy, says infectious disease researcher Nicky Boulter with the Sydney University of Technology. The toxoplasma gondii parasite can only sexually reproduce in cats, but it can live in other creatures, including rats and humans. The parasite changes rats’ behaviors, making them less fearful of cats. This makes the rodents easier prey for the cats, and makes it possible for the parasite to sexually reproduce inside its new feline hosts.

But toxoplasmosis may have much the same impact on humans, Boulter says. Weirdly, she says the effects depend on the host’s gender. “In short, it can make men behave like alley cats and women like sex kittens.” Or, more precisely:

Infected men have lower IQs, achieve a lower level of education and have shorter attention spans. They are also more likely to break rules and take risks, be more independent, more anti-social, suspicious, jealous and morose, and are deemed less attractive to women.

On the other hand, infected women tend to be more outgoing, friendly, more promiscuous, and are considered more attractive to men compared with non-infected controls.

There’s evidence that this parasite has a role in schizphenia, according to the source of all lies. Humans get it from eating undercooked meat that has the eggs, or by accidentally ingesting cat shit.

The really scary statistic is that 33.1 percent of Americans have antibodies for toxoplasmosis — and the parasite never really goes away, even with antibiotics. So up to a third of the U.S. population could be dumber and sexier thanks to a catshit-traveling parasite. France has an estimated rate of infection of between 45 and 88 percent (steak tartare?) and Brazil’s infection rate is estimated at 66.9 percent. By contrast, only 4.3 percent of South Koreans have the parasite.

But press reports about the wacky behavior of people with the parasite may be overstated, an Oxford biologist told the UK Guardian in 2003:

“We don’t want people to go into a panic and think they’re going to behave really strangely, because the problem is once we’ve got it we’ve got it for life,” says Joanne Webster, a biologist at the University of Oxford who studies the parasite. “And in the vast majority, 99% of people or above, the results will be very subtle.” For those that are interested, a simple blood test for antibodies raised against the parasite can tell you whether you’re infected or not.

Transgender people aren’t the monolithic community we may appear from the outside. For every MTF transsexual who insists that she was always a woman inside and she corrected her male body to match her brain, you can find someone who questions whether categories like “man” and “woman” are absolutes after all. (I’ve been reading Undoing Gender by Judith Butler, which is by far her most readable book, and has taken my breath away several times. She attacks the idea of gender as a social construct from a new, ingenious standpoint, by showing how our personhood — and hence our gender — can be “undone” by grief or loss or social crap.) But the woman-brain-in-a-man-body school of thought (or its reverse, for FTMs) remains the mainstream view of trannies. And it’s won the support of some very iffy Dutch science:

[I]nvestigators from the Netherlands Institute for Brain Research in Amsterdam reported preliminary evidence that transsexuals may be inherently different, after all. Their study of six male-to-female transsexuals showed that a tiny structure deep within a part of the brain that controls sexual function appeared to be more like the type found in women than that found in men. If confirmed, the study seems likely to challenge long-held beliefs about what it takes to make someone a man–or, a woman.

The facts: the researchers dissected the brains of six (just six!) post-op transsexuals. They compared them with brains of straight and gay men, and women. The region of the hypothalamus that the researchers claim is different in MTFs than in men (the central subdivision of the bed nucleus of the stria terminals) is “smaller than a pinhead” and you can’t even see the differences using an MRI. The researchers claim, with absolute confidence, that they know the “bed nucleus” “controls sexual function.” The scientists say the “bed nucleus”

measures about 2.6 cubic millimeters, about the size of the colorful, spherical head of a pushpin. In women, it averages 1.73 millimeters, and in transsexuals the average figure is 1.3.

Some other experts were skeptical, the article linked above says. All of the TSs who were dissected had taken estrogen for years, and maybe that changed the size of this region of the hypothalamus. Or maybe the stress of living as a trans person changed the size of their “bed nucleus”. And then there’s this:

Dr. S. Marc Breedlove of the University of California at Berkeley, who wrote an editorial that accompanies the new report, said that the function of the bed nucleus in human behavior, sexual or otherwise, remained “a complete black box.”

So we don’t even know what it is, or what it does. Or what its size signifies.
The reason this research bugs me has very little to do with me and my fellow trans people. It’s more my fear that we’re being used as wedge to push an essentialist agenda. It’s not too far from saying “transsexuals have women’s brains” to claiming “men’s and women’s brains are totally different.” And from there, to claiming that women have less good spatial sense than men. And from there, to claiming there’s an innate biological difference between men’s and women’s math abilities, says Richard Francis, author of Why Men Won’t Ask For Directions:

Evolutionary psychologists assume that it’s biological, that there are hormones involved, that testosterone somehow makes men better spatial navigators. But, the evidence for that is extremely weak. In fact, I spent much of the time writing this book having to read that kind of literature. Whereas there’s ample evidence that social-cultural factors play an enormous role in this. And also this spatial cognition story extends to sex differences in mathematics. For example, the sex differences are most pronounced in the United States, even in the Western world. In some cross-cultural studies, they’ve shown that in African-Americans and Hispanics that females are superior in mathematics, and in Asian-Americans it has been found that the sex difference is quite small. And, then there’s evidence that these sex differences are disappearing over time, which you would expect given the new educational opportunities available to females. And, this does not accord well with a biological explanation, much less an evolutionary explanation.