Homosexuality has always, and most likely will continue to be a subject to controversy. It has been looked upon as “a choice” of lifestyle and “a decision” for many years. Only recently have geneticists been looking at the common biological traits of gay men. A vast amount of studies done by international research teams, including ones from the UCLA (University of California, Los Angeles) David Geffen Medicine School, have found that gay males are more likely to be left-handed, younger siblings of older brothers, and to have hair that whorls in an anticlockwise direction. These traits have led to a growing conformity that sexual orientation is decided before birth on an innate combination of genetic and environmental factors.
Homosexuality refers to the “attraction or sexual behaviour between people of the same sex, or to a sexual orientation.” Both males and females can be of this orientation but in modern society, homosexual men are known as gay and females are known as lesbians. However, the genetic traits that supposably attract males to the same sex are more studied than that of females as no genetic similarities are common enough with in lesbians.
The reason for the start of this research was mainly due to the high correlation of sexual orientation in identical twins which steered towards a genetic component. As well frequency in homosexual males is higher when those males belong to a maternal line of homosexuality in other males. This frequency however is not the same in females but females in the maternal line of male homosexuals were indicated more fertile than other women shown from the work of Camperio Ciani. In this world things happen for a reason. Males are attracted to females for reproductive purposes, so maybe homosexuals are here so that some women are more fertile.
A large set of models were examined by the researchers and excluded individually if they implied that alleles would go extinct too easily or overtake the population. The paper concluded that the only model that fit the empirical data was based on sexually antagonistic selection, based in particular on two genes, at least one of which must be on the X chromosome, which determines the maternal genes in male babies. This model implies that there is an interaction between male homosexuality and increased female fertility. These complex dynamic results in the maintenance of male homosexuality at a stable but low frequency, as well as a hereditary effect on male homosexuality through the female line.
This model could potentially change the focus of opinions on male homosexuality. For instance, perhaps homosexuality should not be seen as a trait that is detrimental to a population because of the reduced male reproduction it implies, but rather in context of providing gender specific benefits by promoting female fertility. This could be an explanation for the evolutionary origin of this genetic trait in humans.
References
www.medicalnewstoday.com/articles/111843.php
findarticles.com/p/articles/mi_m1200/is_n19_v148/ai_17884162/
http://www.genetics.ucla.edu/gendercenter/news.html
http://en.wikipedia.org/wiki/Homosexuality
