[extropy-chat] Gay spandrels?

[Damien Broderick]

At 06:50 PM 7/20/2005 -0400, David Lubkin wrote:

>There is an unpopular hypothesis that homosexuality is a side effect of a 
>viral infection. It is not inherently implausible, given what we're 
>learning about the interrelationships between neurochemistry and behavior. 
>It would be difficult, however, to conclusively confirm or rebut.
>...
>
>What if we then identify the virus and create an effective anti-viral 
>treatment, so that we now have the technical means to reliably convert 
>someone either to homosexual or to heterosexual?

Greg Egan had a story on this general theme a decade or so back. Sorry, my 
library's too far away to check the title or the details. As I recall, 
women were encouraged to use a device that optimised the uterine 
environment, and this had the unforeseen side effect of reducing those 
conditions conducive to the developmental biases likely to express 
themselves in gay sentiments and behaviour.

Off the top of my head, various other possibilities suggest themselves. I 
seem to recall that more boys who become homosexual are born shortly after 
a war, and so too with sons born after several other sons to the same 
mother. The former, I think, was attributed to heightened stress hormones 
altering the uterine environment; the latter to changes induced in the 
mother's body by the previous presence of hormones from boy babies.

Suppose the likelihood of this developmental pathway being expressed is 
enhanced in older mothers having babies for the first time. Suppose that 
population pressures worldwide--and other tendencies toward one child 
families after the demographic transition--lead to fewer homosexually 
biased phenotypes.

Or suppose that the majority of women postpone pregnancy until as late as 
possible. Further, in the latter case, suppose very many young women 
routinely store frozen ovarian tissue for implantation in later life, both 
to forestall ageing and to permit pregnancy in their 50s, say.

Any of these modifications might imaginably skew the uterine environment in 
ways that massively decrease or increase the number of gay male offspring. 
(Perhaps similar effects govern the likelihood of lesbian attachments, but 
that seems less clear, as I recall dimly from my reading.)

Such influences would be spandrels in Gould's sense. Neither adaptations 
nor weird chosen perversions nor wonderfully embraced opportunities -- but 
biases introduced or modified until now by accident.

All this might be complete nonsense, of course.

Damien Broderick