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."