Thursday, June 18, 2015

Brain/body mismatch?

The medical evidence for a mismatch between brains and bodies is ambiguous. The two studies cited most frequently by transgender activists, published in 1995 and 2000, examined the brains of a total of seven male-to-female transgenders and found that a region of the hypothalamus, an almond-shaped area of the brain that controls the release of hormones by the pituitary gland, was female-typical in those brains. But those studies have been criticized for not controlling for the estrogen — which affects the size of the hypothalamus — that most male-to-female transgenders take daily in order to maintain their feminine appearance.

1 comment:

  1. I wonder if the Weekly Standard's 1995 and 2000 studies the same studies as the following studies:

    Zhou JN, Hofman MA, Gooren LJ, Swaab DF. A sex difference in the human brain and its relation to transsexuality. Nature 1995; 378:68.

    Kruijver FP, Zhou JN, Pool CW, et al. Male-to-female transsexuals have female neuron numbers in a limbic nucleus. Journal of Clinical Endocrinology & Metabolism 2000; 85:2034.

    If so:

    1. I agree with the Weekly Standard about small sample size. However, it wasn't 7 people, but rather the 1995 study had 6 participants, while the 2000 study had 42 participants. Still, 6 is too small to be meaningful. As for the 42, not all of the 42 were actually trans. Only 7 were trans (6 women, 1 man). 6 people with sex hormone disorders. Most the rest were presumed by the study to be heterosexuals and homosexuals.

    2. Kruijver et al (2000) notes: "The number of neurons in the BSTc of male-to-female transsexuals was similar to that of the females (P = 0.83)."

    A p value of 0.83 is highly inconclusive. Or to put it another way, the study itself concludes its statement isn't significant, and if the study doesn't put much stock in itself based on its own statistical calculations, then why should we?

    3. A point of correction (if they're referring to the same studies). These two studies didn't look at the hypothalamus but rather the bed nucleus of the stria terminalis (BSTc). The hypothalamus and BSTc are decidedly different parts of the brain. However, for reasons already discussed here and elsewhere, this doesn't necessarily mean there's a scientific basis for transgenderism. And even if there were a scientific basis, it doesn't necessarily mean it is therefore morally licit or medically beneficial for transgenders to become transsexuals.