Mauricio Cabrera are gay brothers who are convinced their
sexual orientation is as deeply rooted as their Mexican
ancestry. They are among 1,000 pairs of gay brothers
taking part in the largest study to date that seeks
genes which might influence whether people are gay.
The Cabreras hope
the findings will help silence critics who say
homosexuality is an immoral choice.
If fresh evidence
is found suggesting genes are involved, perhaps
homosexuality will be viewed as no different than other
genetic traits like height and hair color, said Julio,
a student at DePaul University in Chicago.
Adds his brother:
''I think it would help a lot of folks understand us
funded study, led by Chicago-area researchers, will rely on
blood or saliva samples to help scientists search for
genetic clues to the origins of homosexuality. Parents
and straight brothers also are being recruited.
results aren't expected until next year -- and won't
provide a final answer -- skeptics are already attacking the
methods and disputing the presumed results.
have shown that sexual orientation tends to cluster in
families, though that doesn't prove genetics is involved.
Extended families might share similar child-rearing
practices, religion, and other beliefs that could also
influence sexual orientation.
involving identical twins, often used to study genetics
since they share the same DNA, has had mixed results.
One widely cited
study in the 1990s found that if one member of a pair of
identical twins was gay, the other had a 52% chance of being
gay. In contrast, the result for pairs of non-twin
brothers was 9%. A 2000 study of Australian identical
twins found a much lower chance.
Alan Sanders of
Evanston Northwestern Healthcare Research Institute, the
lead researcher of the new study, said he suspects there
isn't one so-called gay gene.
It is more likely
there are several genes that interact with nongenetic
factors, including psychological and social influences, to
determine sexual orientation, said Sanders, a
Still, he said,
''if there's one gene that makes a sizable contribution,
we have a pretty good chance'' of finding it.
Many gays fear
that if gay genes are identified, it could result in
discrimination, prenatal testing, and even abortions to
eliminate homosexuals, said Joel Ginsberg of the Gay
and Lesbian Medical Association.
added, ''if we confirm that sexual orientation is an
immutable characteristic, we are much more likely to get the
courts to rule against discrimination.''
There is less
research on lesbians, Sanders said, although some studies
suggest that male and female sexual orientation might have
different genetic influences.
His new research
is an attempt to duplicate and expand on a study
published in 1993 involving 40 pairs of gay brothers. That
hotly debated study, wrongly touted as locating ''the
gay gene,'' found that gay brothers shared genetic
markers in a region on the X chromosome, which men
inherit from their mothers.
That implies that
any genes influencing sexual orientation lie somewhere
in that region.
to duplicate those results failed. But Sanders said
that with so many participants, his study has a better
chance of finding the same markers, and perhaps others
on different chromosomes.
If these markers
appear in gay brothers but not their straight brothers
or parents, that would suggest a link to sexual orientation.
The study is designed to find genetic markers, not to
explain any genetic role in behavior.
And Sanders said
even if he finds no evidence, that won't mean genetics
play no role; it may simply mean that individual genes have
a smaller effect.
Stanton Jones, a psychology professor and provost at
Wheaton College in Wheaton, Ill., a Christian school. Jones,
an evangelical Christian, last month announced
results of a study he coauthored that says it's
possible for gays to "convert," changing their sexual
orientation without harm.
Jones said his
results suggest biology plays only a minor role in sexual
orientation, and that researchers seeking genetic clues
generally have a pro-gay agenda that will produce
''We do not have
a predetermined point we are trying to prove,'' he said.
''We are trying to pry some of nature's secrets loose with
respect to a fundamental human trait.''
acknowledged that he's not a neutral observer. His study
involved 98 gays ''seeking help'' from Exodus
International, a Christian group that believes
homosexuals can become straight through prayer and
counseling. Exodus International funded Jones's study.
president, Alan Chambers, said he became straight and
believes homosexuality is morally wrong.
Even if research
ultimately shows that genetics play a bigger role, it
''will never be something that forces people to behave in a
certain way,'' Chambers said. ''We all have the
freedom to choose.''
brothers grew up in Mexico in a culture where ''being gay
was an embarrassment,'' especially for their father,
said Mauricio, 41, a car dealership employee from
They had cousins
who were gay, but Mauricio said he still felt he had to
hide his sexual orientation and that he struggled with his
''double life.'' Julio said having an older brother
who was gay made it easier for him to accept his
Jim Larkin, 54, a
gay journalist in Flint, Mich., said the genetics study
is a move in the right direction.
difficulties of being gay in a predominantly straight
society, homosexuality ''is not a choice someone would
make in life,'' said Larkin, who is not a study
He had two
brothers who were gay. One died of AIDS complications; the
other committed suicide. Larkin said he didn't come out
until he was 26.
''I fought and I
prayed and I went to Mass and I said the rosary,''
Larkin said. ''I moved away from everybody I knew...thinking
maybe this will cause the feelings to subside. It