Gay real brothers
Gay people often have older brothers. Why? And does it matter?
The Science of Siblings is a new series exploring the ways our siblings can guide us, from our money and our mental health all the way down to our very molecules. We&#;ll be sharing these stories over the next several weeks.
This is something I learned years ago through gay bar chatter: Gay people are often the youngest kids in their families. I liked the notion right away — as a gay youngest sibling, it made me feel like there was a statistical order to things and I fit neatly into that order.
When I started to report on the science behind it, I learned it&#;s true: There is a well-documented correlation between having older siblings (older brothers, specifically) and a person&#;s chance of being gay. But parts of the story also struck me as strange and dark. I thought of We the Animals, Justin Torres&#; haunting semi-autobiographical novel about three brothers — the youngest of whom is queer — growing up in New York state. So I called Torres to acquire his take on the idea.
Torres&#; first reacti
Why gay men often possess older brothers: &#;Many confirmations that this pattern exists&#;
Researchers are further exploring the notion that having an older brother increases a man&#;s chances of being gay.
&#;This pattern has been documented around Canada and the United States, but it goes well beyond that,&#; Stetson University psychology professor Scott Semenyna told NPR this week.
&#;There&#;s been now many confirmations that this pattern exists in countries like Samoa,&#; he continued. &#;It exists in southern Mexico. It exists in places fond Turkey and Brazil.&#;
Known since the s as the fraternal birth order effect, it has been theorized that men have roughly a 33% increased probability of being attracted to men for every older brother they hold, according to Semenyna.
Those with one older brother have an approximate % probability of being gay &#;and then that probability would increase another 33% if there was a second older brother, to about %,&#; he explained.
People with five older brothers possess about an 8% chance.
Potential connections and possible biological
New research shows having a greater number of older brothers increases the probability of a person entering a same-sex union at some point in their lives.
This finding, detailed in our paper published today in the Journal of Sex Research, offers a rare insight into the origins of sexual orientation.
The origins of sexual orientation
In recent decades, many countries have achieved extraordinary progress towards equal treatment of LGBTIQ+ people, including greater common support and more protective legislation. But despite these encouraging developments, sexual minorities still experience elevated levels of stigma – and the origins of sexual orientation remain a matter of debate.
Read more: How stigma impacts LGB health and wellbeing in Australia
A growing body of research is attempting to shed light on why some people experience same-sex sexual attraction and others don’t. These studies own substantial implications for public belief and debate, and subsequently the treatment of LGBTIQ+ people.
For example, we know people who view sexual orientation as a product of biol
Astral Codex Ten
In the s, Blanchard and Bogaert proposed the Fraternal Birth Order Effect (FBOE). Men with more older brothers were more likely to be gay. “The odds of having a gay son increase from approximately 2% for the first born son, to 3% for the second, 5% for the third and so on”.
This started as a purely empirical finding. If you surveyed enough men, you would find it was accurate, even though no one knew why. In , Bogaert establish that the effect applied only to biological siblings and not adoptive ones, suggesting a physiological cause. He proposed a mechanism based on H-Y antigens, a set of molecules on male cells involved in sexual development. If a mother has many male pregnancies, her immune system might become gradually more sensitized to H-Ys, start attacking them, and interfere with later fetuses’ sexual development.
In , scientists announced tentative confirmation: antibodies to a male protein called NLGN4Y seemed more common in the mothers of gay sons than in men, non-mothers, and mothers of straight people.
It seemed verb the FBOE was ready to coast into th