Do you have an older brother? Then you may be gay, according to the study. Scientists have figured out what influences same-sex attraction
Some believe that same-sex attraction is something unnatural and that it is just a momentary pose. But academics from several Australian universities (including Czech Jan Kabátek) offer a very strong counter-argument to this view. In January this year, they published the results of their study, which showed what specifically influences homosexual orientation. And as the fresh research confirmed, homosexuality has a biological basis.
The academic team took inspiration from scientific papers that have looked at fraternal birth order in the past. Indeed, this is one of the best-documented patterns that influences the biological origins of human sexual orientation. The authors of previous studies have been led by this finding to hypothesize that the likelihood of male homosexuality increases with the number of older biological brothers that men have.
This is thought to be due to the mother's immune response to proteins produced by the male fetus. These proteins then enter the mother's bloodstream and trigger the production of antibodies that predispose the sexual development of subsequent children. And given that these maternal antibodies accumulate in the mother's body during successive pregnancies with just male fetuses, it can be assumed that men with multiple older brothers are also more likely to be homosexual.
However, despite the fact that several researches have already addressed the topic, many people have not attached much importance to them. They doubted their veracity, mainly because they felt that the research did not work with a sufficiently representative sample of the population. But the new study corrected this mistake by using data from Dutch population registers tracking the life histories of more than nine million people born between 1940 and 1990. We therefore considered them to be representative of the homosexual community," the authors of the current study explained.
But this was not the first time academics had worked with such a large dataset. "In previous studies, we have used it, for example, to compare the academic performance of children raised by same-sex and different-sex couples," the researchers described. And what did they find this time?
"The results provide clear evidence of the effect of fraternal birth order on homosexuality. Men with one older brother are 12% more likely to ever enter a same-sex union than men with one older sister, and even up to 21% more likely than men with only one younger brother or sister," the academics said.
In addition to birth order, the total number of siblings also emerged as a key factor. Men who are born the youngest have a greater "propensity" to homosexuality than men who are, in contrast, the oldest among siblings. And the differences widen as the total number of siblings increases.
"For example, if a man has three older brothers, he is 41% more likely to be attracted to the same sex in the future than if he has three older sisters, and even 80% more likely than if he has three younger brothers," the authors explain, adding that the sex of younger siblings plays no role in (homo)sexual orientation.
The researchers also examined the same in women. Here too, surprisingly, the likelihood of homosexuality increases with the number of older brothers. "These findings support the assumption that maternal antibodies and proteins produced by male fetuses also influence the sexual development of females," the study authors added.
The academics hope that the results of their research will not only serve to understand how sexual orientation actually arises, but they also believe that the study will help lead to a greater level of tolerance. The diversity of sexual orientation is not a matter of succumbing to passing trends, but has a natural biological basis. This is probably why we know many homosexual stories from antiquity. Even if some hardened people's opinion is unlikely to be changed by research, at least it shows that abhorrent practices such as conversion therapy simply cannot change someone's sexual orientation. It is possible to have a negative view of homosexuality, but it cannot be unlearned or erased.
