Scientists May Have Finally Unlocked Puzzle of Why People Are Gay - US News and World Report

Scientists may have finally solved the puzzle of what makes a person gay, and how it is passed from parents to their children.

A group of scientists suggested Tuesday that homosexuals get that trait from their opposite-sex parents: A lesbian will almost always get the trait from her father, while a gay man will get the trait from his mother.

Long thought to have some sort of hereditary link, a group of scientists suggested Tuesday that homosexuality is linked to epi-marks — extra layers of information that control how certain genes are expressed. These epi-marks are usually, but not always, “erased” between generations. In homosexuals, these epi-marks aren’t erased — they’re passed from father-to-daughter or mother-to-son, explains William Rice, an evolutionary biologist at the University of California Santa Barbara and lead author of the study.