Homosexuals appear more likely to be left-handed than the general population, a Canadian study showed Wednesday.
Researchers at McMaster University in Hamilton, Ontario, studied 38 homosexual men and 32 homosexual women and classified them as left-handed if they performed at least one of 12 simple manual activities such as lighting a match with their left hand.Among the women, 69 percent were either mixed or left-handed. Among men, 45 percent were "lefties." In addition, a followup study found an even greater percentage of homosexual men were left-handed, the researchers said.
In the general population, about 10 percent of people write left-handed, while 30 percent favor their left hand in a variety of activities.
A greater prevalence of left-handedness among homosexuals suggests their "brain organization may be different than others," said Dr. Sandra Witelson, co-author of the study.
The study is part of a larger ongoing effort to look at the biological and environmental roots of human behavior.
Witelson speculated that hormonal levels during fetal development may affect brain organization. Lesbians may be exposed to an excess of male hormones when they are in their mother's womb, while the mothers of homosexual men may not produce enough of the same hormones, she said.