By Andy Coghlan. Italian geneticists may have explained how genes apparently linked to male homosexuality survive, despite gay men seldom having children. The researchers discovered that women tend to have more children when they inherit the same — as yet unidentified — genetic factors linked to homosexuality in men. They found that female relatives of gay men had more children on average than the female relatives of straight men. Mothers of gay men produced an average of 2. And maternal aunts of gay men had 2. Camperio-Ciani stresses that whatever the genetic factors are, there is no single gene accounting for his observations.
Survival of genetic homosexual traits explained
Biology and sexual orientation - Wikipedia
In the Aug. In a large study of more than , men and women in the United States, United Kingdom and Sweden, researchers discovered four genetic variants that occur more often in people who indicated on questionnaires that they had had same-sex sexual partners. The other two influence sex partner choice for both men and women. Collectively, the DNA differences explained only 8 to 12 percent of the heritability of having same-sex partners. Researchers examined DNA data from more than , participants in the U. Biobank and more than 69, people who had their DNA tested by the consumer testing company 23andMe.
"Gay Genes" May Be Good for Women
The relationship between biology and sexual orientation is a subject of research. While scientists do not know the exact cause of sexual orientation , they theorize that a combination of genetic, hormonal, and social factors determines it. Biological theories for explaining the causes of sexual orientation are favored by scientists  and involve a complex interplay of genetic factors, the early uterine environment and brain structure. A number of twin studies have attempted to compare the relative importance of genetics and environment in the determination of sexual orientation.
Last updated November 10, at pm. This is often used by those who would argue against the biological nature of same sex attraction, by treating biological factors as immutable, a fixed point in human development. The science suggests that this is not the case. Jenny Graves, professor of genetics at LaTrobe University in Melbourne, has no problem with the concept of gay genes.