The biology debate

A considerable body of research points to a biological basis for
sexual orientation



   "What did I do wrong?"
   Many lesbians and gay men have faced this difficult question
when coming out to their parents. The answer has usually been
something along the lines of "Nothing," or "I've always known I was
this way," or "I think I was born gay." 
   Unfortunately, there has never been hard scientific proof to
back up these assertions. But as Oscar Wilde once observed, science
is always making wonderful improvements on things. There is
mounting evidence that sexual orientation is the complex effect of
processes that begin well before birth.
   The significance of research into the causes of sexual
orientation may be profound. 
   On the one hand, scientific research has conclusively put to
rest the harmful myth that homosexuality is a sexual "preference"
or lifestyle choice.  
   But it also raises the spectre of eugenic cleansing, or weeding
out the "unfit" through prenatal genetic testing. We must be very
careful about how we use the knowledge we gain from research.
   What we know about sexual orientation remains fairly limited,
and draws on research in a number of fields: psychiatry, the
anatomy of the brain, hormonal activity, and genetics.

"Curing" homosexuality

   Psychiatrists first turned their attention to homosexuality
decades ago. They assumed that what had been treated historically
as a sinful or criminal activity was instead a form of mental
illness. Gay historians have documented plenty of shocking cases of
individuals "cured" of their homosexuality through such treatments
as lobotomies, castration and crude electric shock therapies.
   What researchers were unable to do is demonstrate either that an
individual could choose to be homosexual, or that there was a
psychological profile that was consistently and demonstrably
homosexual. In short, there was nothing empirically observable to
suggest a fundamental psychological difference between homosexuals
and heterosexuals.
   More recently, studies of the anatomy of the brain have led to
the suggestion that certain regions of the brain vary between males
and females and, moreover, that particular regions may also vary
with sexual orientation, at least among males.
   The evidence draws on studies of rat brains, but is based
primarily on a 1991 study of brain tissues taken during autopsies
from individuals who died in New York and California hospitals.
   The evidence to date is suggestive, not conclusive. And a firm
link between anatomy and sexual orientation still doesn't answer
the tantalizing question, "Why?"
   Hormonal activity may suggest answers. Other studies of rats
have observed remarkable changes in sexual behaviour in both
castrated males injected with estrogen and females injected with
testosterone.
   Some scientists suggest that the hormonal effects that count are
those that take place in the womb. One hint: an unusually high
proportion of women identifying themselves as lesbian or bisexual
appear to have been exposed prenatally to much higher levels of
male hormones than usual.

A gay gene?

   The high incidence of shared sexual orientation among identical
twins, who share the same genetic code, has encouraged geneticists
to explore the possibility that the human genetic code includes
instructions for gay traits, including non-sexual behaviour.
   Genetic studies of generations of fruit flies have demonstrated
harmless evolutionary changes to genes that have led to consistent,
complex behaviour patterns that may be analogous to human
homosexual activity.
   As with the rat studies, the analogy is surely oversimplified,
and if there is a genetic basis for homosexuality it is probably a
complex combination of effects from a number of genes. Preliminary
studies of human samples also point to genetic influence on sexual
orientation.
   These studies in different scientific fields are clearly
pointing towards the conclusion that there is a biological basis
for sexual orientation. What we don't yet know is what effect (if
any) one's childhood environment may have on adult sexual
behaviour.
   But the progress of research does suggest that in a few years,
we'll be able to point to the latest biology textbook to explain
why we are what we are.






...scientific research has conclusively put to rest the harmful
myth that homosexuality is a sexual "preference" or lifestyle
choice.


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