Gay germ theory and city size at age 16: A reader in the comments section of my post on the residential distribution of adult homosexuals raised the claim by Gregory Cochran that a same-sex orientation is caused by some pathogen. In support of the idea, Cochran cited research finding that gay men raised in or near a city outnumber gay men raised in less populated by a margin three to one, or something like that.
Most people in the comments, including myself, assumed that the greater concentration of homosexuals in cities is due to migration, but let's look at where homosexuals are at age 16 (H/T to TGGP who reminded me of the variable).
Percent of the total sex-specific population at age 16, N = 18,012
Town (lt 50,000) 2.9
City (50,000-250,000) 3.5
Big city--suburb 3.3
City (gt 250,000) 3.8
Town (lt 50,000) 1.6
City (50,000-250,000) 1.9
Big city--suburb 2.0
City (gt 250,000) 2.3
Here we see that as a place is more populated, prevalance rates for both gay male adolescents and lesbian teenagers increase. Why we see this pattern here, but not for adult lesbians, as shown in the last post, I'm not sure. This is a larger and thus more precise sample. That might be the answer.
So, we see more gays and lesbians in cities even before they are old enough to migrate to them. How do we explain the pattern? Perhaps families with a tendency to have homosexual offspring are drawn to cities. Perhaps homosexuals from smaller towns are less willing to admit their orientation (although they are asked the question, not when they are 16, but later when they are adults). Or perhaps Cochran is right. Comments?