Fingerprints
suggest gay link
Researchers
say higher percentage have more ridges on left hand
Washington
- Two Canadian researchers have found a link between the number
of ridges in fingerprints and male homosexuality, adding to
the theory that sexual orientation is determined before birth.
The researchers,
working at the University of Western Ontario, compared the number
of ridges on the fingertips of 66 homosexual men with 182 heterosexual
men.
Thirty percent
of the homosexual men showed more ridges on their left hands
than their right, while only 14% of the heterosexual men showed
the same pattern.
Most men
and women have more ridges on their right hands. Fingerprints
are completely developed in fetuses by about the 16th week after
conception, and are largely genetically determined.
"This
certainly suggests sexual orientation is somehow determined
by prenatal events," said researcher Doreen Kimura.
The study
appears in the December issue of Behavioral Neuroscience.
Kimura and
the study's lead author, graduate student Jeffrey Hall, said
the fingerprint patterns are not distinctive to gay men or a
marker of homosexuality. Most homosexual men show the more typical
pattern of more ridges on the right hand, they noted.
"What
we found is a statistically significant difference between groups
of heterosexual and homosexual men," Kimura said.
Roger Gorski,
a UCLA neurobiologist who has done extensive research on sexual
differentiation called the study "another suggestion that
there's a biological component to sexuality." But he said
he had some trouble with making the connection between ridges
on the fingers and sexual orientation.
"The
way I like to summarize it is sexual orientation is a multifaceted
behavior and it's unlikely that one gene, that one hormone,
that one environmental experience--or that one fingerprint--is
going to be an explanation for everything," he said.
Kimura is
also known for her work on differences between men and women,
ranging from problem-solving ability to brain hemisphere differences.
She speculates
that there is a link between finger ridge patterns and the development
of the nervous system. Many of the gay men with more ridges
on their left hands were also left-handed. Research has identified
a higher incidence of left-handedness among gay men and lesbians
than in the general population.
The team
also found a difference in hearing. Most people report words
spoken to the right ear more accurately than words spoken to
the left ear. The right ear is directly linked to the brain's
left hemisphere, which controls speech.
However,
Kimura and Hall found some gay men could hear equally well out
of both ears. This might be due to better transmission between
the brain's hemispheres, Kimura said.
