Recently, same-sex marriage is recognized legally in California U.S.A and Norway. It is demonstrated that homosexuality owns partly to heredity which is a profound progress scientists have made in the research about it. Although the kids of the same-sex are pretty less than the ones of the heterosexual, the so-called “gay genes” pass down in crowds proved by the facts. An interesting idea occurs in the new research that these genes promote feminine fertility, which has been issued on PLoS ONE in the form of research paper on 18th Jane.
No related gay genes have been separated, but it is illustrated by many researches that gays have more gay relatives in maternality that that in paternality. Some scientists formulate a hypothesis that the gay genes may be a kind of X-linked genes.
A research paper issued by the group led by the Italian evolutionary psychologist Andrea Camperio Ciani from University of Padua in 2004 shows that the women who have gay relatives give birth to more children compared to those with heterosexual relatives. The gap seems extraordinarily great —— for example, the women who have gay relatives have 2.7 kids on average while those with heterosexual relatives have 2.3 per capita. This trend is also found among maternal aunts.
In the latest research, Camperio Ciani and his colleagues take around 20 results, including the member of the gay genes and the advantages in fertility arisen by the genes which are the X-linked genes or others, into consideration applying the mathematical model to seeking the theories to explain the phenomenon.
It is found that the model to explain the foregoing figures contains 2 gay genes at least one of which is X-linked gene. These genes promote feminine fertility while decrease male fertility which is called sexual antagonism once studied in the field of insects and mammals.
The research group says that these gay genes actually perhaps increase the attraction of the men of women to the men instead of the former result that they feminize the gays. These genes, the threats to men, do good to feminine fertility, so they keep the gays survive in the crowds though only occupying a small portion in the people.
Geneticist Dean Hamer from National Cancer Institute, also the pioneer in seeking gay genes believes that this research result is “an accurate mathematical analysis”. He says that this research has formulated a simple solution of the Darwinian paradox caused by the homosexual. He also states that the “gay genes” in men are equal to the “super heterosexual genes” in women.
（PLoS ONE，doi:10.1371/journal.pone.0002282，Andrea Camperio Ciani，Giovanni Zanzotto）