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from "Born that way" theory
Homosexuality and Genes:
Déjà vu All Over Again?
By Warren Throckmorton, PhD
Grove City College
Reprinted by permission from Grove City College
(October 30, 2003) -- It's like déjà vu all
over again. Another study claiming to support the idea that
homosexuality is directly caused by genes comes to public
attention. And then there are the journalists eager to
trumpet the headline. Alas, as in the past, the reports and
public statements of the authors misrepresent and hype the
study beyond recognition.
For instance, there is the "blinking" study reported
recently in the Behavioral Neuroscience journal. Lead
author Qazi Rahman has become a leading opponent of the idea
that environment may play a crucial role in the formation of
same-sex attraction. Columnist Nicholas Kristof thought so
much of this study that he quoted it in a recent New York
Times article as being important evidence of a gay gene.
Although Rahman's theories are more hormonal than genetic,
the researcher does negate the role of environment in
sexuality. Why? One reason is that when startled, 15
lesbians on average blinked in a similar manner to 15
straight men. There were no differences between straight and
gay men.
Wait, no difference between gay and straight men? From
reading Kristof's recent piece and the press accounts of the
study, you would not know that. Because a small group of
lesbians blinked like a small group of straight men, the
leap is made to assume being a lesbian is obligatory? The
inference is confounded by the fact that it is well known
that smoking can impact startle response, and Rahman's study
did not take smoking status into account in choosing study
participants.
Hence, the headlines for the Rahman study could easily have
read: "Sexual orientation not genetic for gay men; might be
for lesbians." I must have blinked; I didn't read that
anywhere.
In his Times article, Kristof then quotes another Rahman
article from the journal, Personality and Individual
Differences, that speculates that 50-60% of the differences
in sexual orientation are due to genetic influences. Kristof
and others in the media uncritically accept these numbers
even though there is a considerable debate in scientific
circles about the validity of the 50-60% figure, and the
twin research on which it is based. Despite a couple of
fairly sophisticated attempts, efforts by independent
researchers to confirm these numbers have failed.
So what you wouldn't know if you only read the news services
is that the data are highly questionable and there are
findings in these studies that better support environmental
hypotheses concerning sexual orientation.
Even if we did assume that differences in sexual orientation
were 50-60% genetic, what would that mean? Well, first of
all that leaves a pretty substantial portion of sexual
preference open to environmental influence.
So the analogies to left-handedness and eye color fall
absolutely flat.
The Influence of Genes on Other Human Traits
Second, to gain perspective, lets look at other personality
traits and the estimated percent of individual differences
attributable to genetic factors according to existing
research found on the American Psychological Association's
website.
* Attitudes toward reading books - 55%
* Feelings about abortion on demand - 54%
* Feelings about roller coaster rides - 50%
* Attitudes towards the death penalty for murder - 50%
* Humility - 58%
* Likelihood to engage in casual sex - 49%
* Attitudes toward equality - 55%
With these genetic influences, think of the new advocacy
groups that might spring up. Roller-coaster enthusiasts
might lobby for free or reduced admission to theme parks,
since many riders would be hindered from being "who they
are" by restrictive pricing policies. If we thought about
these traits the way the media and some researchers want us
to think about homosexuality, the campaign for safe sex is
futile--since nearly half the reason why certain people drop
their pants on a whim is supposedly due to genetics. And,
as we are getting accustomed to hearing..."can't change that," right?
At risk of belaboring the point, the faulty interpretation
of all of these studies is that genetic influence is the
same as destiny. Arising from studies of identical twins
raised together, these studies frequently fail to take into
account the confounding factor of shared environment.
Despite the flaws in interpretation and design, the
inference desired by many in the gay-activist camp is that
the only scientifically acceptable approach to homoerotic
feelings is to accept and identify with them.
Unless one is prepared to say that about attitudes toward
equality, the death penalty, abortion and literacy...then why
say it about sexual feelings?
Here's one more human trait that is highly heritable: weight
and body type. This trait is estimated to be 60-80% related
to genetic influence. If homosexuality is out of control at
50-60%, then what of one's physique?
I can hear the doors of gyms, fitness centers and
infomercial studios slamming shut now. Why bother to try to
change something so clearly due to genetics? Oh, to have
inherited the six-pack "ab" gene!
There may be one trait that is determined. I guess we could
call it journalistic determinism, because it appears that
many journalists are determined to find that gay gene. I
really shouldn't be so hard on them, they probably can't
help it.
Updated: 2 September 2008
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