Gay Brothers Studied for Clues to Sexual Preference
DNA from 1,000 pairs analyzed for linkages
By Caroline Zimmerman,  Newser User
Posted Aug 11, 2007 3:46 PM CDT
A participant waits for the start of the EuroPride parade in Madrid, Saturday, June 30, 2007. Spain, predominantly Roman Catholic, had for centuries been under the moral guardianship of the church. Homosexuality...   (Associated Press)
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(Newser) – A team of Chicago-based scientists is conducting a large-scale study of gay brothers to learn more about the genetic factors involved in sexual orientation. Similar studies have been too small to be conclusive; this time, scientists recruited 1,000 pairs—10 times the size of previous studies— to contribute DNA samples.

Researchers don't know what kinds of genes linkages to expect; little is known about sexual identity. "The genes would probably be doing their work by affecting sexual differentiation of the brain during prenatal life," one of the project's researches told the Chicago Tribune. "But what scientists are increasingly appreciating is that genes can affect a trait in ways you could never have guessed."