ITALY: Genetic factors, along with cultural and early experiences, influence male homosexuality, Italian scientists said yesterday.
Researchers at the University of Padua said the genetic components were linked to the X chromosome, which is inherited only from the mother. But they are probably on other chromosomes and could partly explain male homosexuality.
"The key factor is that these genes both influence homosexuality in men, higher fecundity in females and are in the maternal and not the paternal line," Dr Andrea Camperio-Ciani, who headed the research team, said in an interview.
More than a decade ago scientists in the United States reported that they had found evidence of a "gay gene" in men. But other researchers questioned the finding when they could not duplicate the results.
Dr Camperio-Ciani and his team suggest there are several genes which could be involved, including those on the X chromosome. In their research, which is reported in the Proceedings of the Royal Society, they found an increase in homosexuality in the maternal line of gay men they studied, which suggested the X chromosome.
"We know that at least one of these genetic factors is on the X chromosome but that is not enough; there must be other genetic factors that are important but are elsewhere," Dr Camperio-Ciani added. The results are based on a study of 98 homosexual and 100 heterosexual men and about 4,600 of their relatives.