Their newly-released report has been spreading on news and science websites around the country.
Jim Matheny has more on the generic switches researchers have discovered which they say explain how sexual preference may be passed from one generation to the other.
Sergey Gavrilets has spent 15 years as a math and evolutionary biology professor at UT. He's picked up plenty of studies that show homosexuality can be linked to families. What researchers have not found is an exact "gay gene."
"In spite of enormous effort people have put toward finding gay genes, nobody has been able to identify them," Gavrilets said.
Gavrilets published a new study in the quarterly review of biology that says instead of a gay gene, there's something more like a power switch that gets passed down from parents. That epigenetic switch tells females to ignore testosterone and tells men to use the hormone.
Normally, these switches are erased. They are not flipped one way or another during fertilization. This new research says some parents pass that switch on. So, a mom's switch can tell her son to ignore testosterone and end up more feminine. Or a dad's switch can tell a daughter to become more masculine.
"And these models that we develop will work for both gays and lesbians. I don't think there's any other theory that works for both," Gavrilets said.
So, his theory says the genetic material is in everyone but gets expressed differently.
"Just think of a book. You cover a piece of text with something else. You're not able to read it. You're not able to express those genes. So genes are still there but are not expressed," Gavrilets said.
Gavrilets says biological researchers are interested in the next step: testing for those epigenetic marks.
Even if the theory is proven, the researchers say it may still just be one of several factors that ultimately determine if someone is homosexual.
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