What causes men to be gay

If it appears in a man's genetic code it will code for same-sex attraction, but so long as this happens rarely the allele still has a net evolutionary benefit. Recently, scientists announced that they found some genes that might be associated with sexual orientation and a biological explanation for the reason gay men tend to have older brothers.

The allele - or group of genes - that sometimes codes for homosexual orientation may at other times have a strong reproductive benefit. It's becoming scientific orthodoxy. The evolution of lesbianism is relatively understudied - it may work in a similar way or be completely different.

Discover the history of sexual science, including the shift in understanding sexual orientation from pathology to normal variance. Development of a homosexual preference might have something to do with the maternal environment a male fetus finds itself in.

Therefore, the theory goes, a low "dose" of these alleles enhances the carrier's chances of reproductive success. But how does it fit with Darwin's theory of evolution? In the last two decades, dozens of scientific papers have been published on the biological origins of homosexuality - another announcement was made last week.

There is some evidence for this second theory. [1][2][3] However, evidence is weak for hypotheses that the postnatal social environment impacts sexual orientation, especially for. But since gay and lesbian people have fewer children than straight people, a problem arises.

Most of the theories relate to research on male homosexuality. The implication is that there is an unknown mechanism in the X chromosome of men's genetic code which helps women in the family have more babies, but can lead to homosexuality in men. It's possible that different mechanisms may be at work in different people.

Since the early s, researchers have shown that homosexuality is more common in brothers and relatives on the same maternal line, and a genetic factor is taken to be the cause. Andrea Camperio-Ciani, at the University of Padova in Italy, found that maternal female relatives of gay men have more children than maternal female relatives of straight men.

A minority of gay people disagree, maintaining that sexuality is a social construct , external , and they have made a conscious, proud choice , external to take same-sex partners. It mocks those who "think it's a decision, and you can be cured with some treatment and religion - man-made rewiring of a predisposition".

Scientists may have finally solved the puzzle of what makes a person gay, and how it is passed from parents to their children. Another way a "gay allele" might be able to compensate for a reproductive deficit is by having the converse effect in the opposite sex. This would compensate for gay people's lack of reproduction and ensure the continuation of the trait, as non-gay carriers of the gene pass it down.

There are two or more ways this might happen. A massive study of half a million people finds no single gene behind sexual orientation, adding more evidence that there is no “gay gene”. But scientific opinion is with Macklemore. The relationship between biology and sexual orientation is a subject of ongoing research.

Macklemore and Ryan Lewis's hit song Same Love, which has become an unofficial anthem of the pro-gay marriage campaign in the US, reflects how many gay people feel about their sexuality. One possibility is that the allele confers a psychological trait that makes straight men more attractive to women, or straight women more attractive to men.

These results haven't been replicated in some ethnic groups - but that doesn't mean they are wrong with regards to the Italian population in Camperio-Ciani's study. Also relevant - although in no way proof - is research identifying physical differences in the brains of adult straight and gay people, and a dizzying array of homosexual behaviour in animals.

Scientists don't know the answer to this Darwinian puzzle, but there are several theories. Every now and then a family member receives a larger dose that affects his or her sexual orientation, but the allele still has an overall reproductive advantage. For example, an allele which makes the bearer attracted to men has an obvious reproductive advantage to women.

The fa'afafine of Samoa dislike being called "gay" or "homosexual". Learn about Alfred Kinsey's contributions, the concept of sexual orientation as a continuum, controversy over conversion therapies, and the biological basis of sexual orientation. While scientists do not know the exact cause of sexual orientation, they theorize that it is caused by a complex interplay of genetic, hormonal, and environmental influences.