Posted: Apr 30, 2012 3:26 pm
Shrunk wrote:But, Thommo, the issue here is the correlation between anal sex and male homosexuality. As you say, "it is entirely unreasonable to suppose that a predilection for anal sex causes men to want to have sex with men." But then you are making the assumption that homosexuality in males causes them to want to have anal sex.
Well it sure as heck doesn't increase their desire to have vaginal intercourse.
Strictly speaking I didn't make that assumption by the way, I have assumed that homosexuals are more likely to practise anal sex than straight men (which I believe is true), but even that isn't a required assumption as the greater homogeneity of the sexual roles of members of the "gay men" category as opposed to the "straight people" category leads to differences in the transmission pattern that sees a greater risk of spreading HIV to more people even with the same rate of practise of anal sex, due to the asymmetry of the transmission rate from the person using the penis and the one using the anus.
Shrunk wrote:Suppose we were to determine that black men are more likely to smoke cigarettes than men of other races and, as a result, have higher rates of lung cancer. Would it be correct to say that being black increases your risk of lung cancer? I think that would be deceptive, if not outright incorrect.
If that were the case and not the result of a spurious correlation (like socio-economic factors that are almost certainly different between blacks and whites), then yes.
A better example might be whether we were to say that being black is a causal factor in having a Primaquine reaction. It is.