Showing posts with label Gay Germ Theory. Show all posts
Showing posts with label Gay Germ Theory. Show all posts

Sunday, May 24, 2009

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

Male homosexuals
Farm 2.3
Country/non-farm 2.8
Town (lt 50,000) 2.9
City (50,000-250,000) 3.5
Big city--suburb 3.3
City (gt 250,000) 3.8

Lesbians
Country/non-farm 1.5
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?

Tuesday, February 24, 2009

More birth seasonality data: As a follow-up to my post on GSS data and the connection of month of birth to a homosexual orientation, I looked at the The National Longitudinal Study of Adolescent Health. They have a larger sample of homosexuals--N = 226 (i.e, ever attracted to a male).


Percent born between August and November (bad months)

Straight boys 34.0
Gay and bisexual boys 34.9


Percent born between January and April (good months)

Straight boys 32.0
Gay and bisexual boys 32.7


No differences here, and a lack of empirical support for "gay germ theory." Keep in mind Agnostic's argument in the last set of comments that birth seasonality is simply not a good test of the theory.

Sunday, February 22, 2009

Gay germ theory and month of birth

You can find a great analysis over at Congenial Times reporting GSS evidence for Cochran's "gay germ theory." According to the theory, homosexuality is caused by infections affecting brain development. The GSS data shows that a disproportionately high number of gay men are born in June. According to the analyst, if an embryo were conceived in September, he would be exposed during the crucial first trimester to the peak flu season, and would then be born in June.

The problem with this is that, according to the CDC, the peak month for flu for the past 26 years has been February (see the graph above). The peak conception month should be December since Mom and embryo are exposed to three bad months. Looking over a longer period, November through February would be the worst 4 months. The best four months for conception would probably be April through July since you are exposed to no months with a particular flu problem. Focusing on the month of birth instead of conception, the worst period should be August through November and the best, January through April.

I'm looking at 4-month periods because the GSS has a small number of homosexual respondents, and cell sizes increase as we merge them. We can also boost sample size by combining homosexuals and bisexuals (as Congenial Times did, N = 167).

Percent born between August and November (bad months)

Straight men 33.9
Gay and bisexual men 34.2


Percent born between January and April (good months)

Straight men 32.9
Gay and bisexual men 28.8


Gay and bisexual men are a bit less likely to be conceived during the low-risk months, but do not differ from straights during the flu season peak. The evidence here for the theory is weak.