Queer Brains

Dr. [Simon LeVay] measured the size of four small areas called interstitial nuclei of the anterior hypothalamus (INAH) 1,2,3, and 4. No significant differences were found in INAH 1,2, or 4. However, INAH 3 was more than twice as large in the straight men as in the gay men or in the straight women. It was about the same size in the gay men and straight women. This finding suggests that INAH 3 is "dimorphic" that is, has two different sizes, depending on sexual orientation. If so, one would expect lesbian brains also to have great big INAH 3's, but lesbian brains are notoriously unpredictable, so don't bet the rent on it. (Although there was one bisexual man grouped with the gay male sample, Dr. LeVay did not address the question of how INAH 3 might vary in bisexual brains.) The possibility that the size difference was related to AIDS was ruled out by data showing no difference in INAH 3 in the straight men who died of AIDS compared to the straight men who died of something else. There were, however, a couple of exceptions: straight men with small INAH 3's and gay men with big ones, so sexual orientation is probably, not the only determinant of INAH 3 size.