One point for the “nature” side of the nature-versus-nurture debate. A new study suggests that certain biological traits — including birth order and handedness — are linked to male sexuality.
Related: Sorry guys, science confirms ‘gaydar’ isn’t real
For the study, newly published in the Proceedings of the National Academy of Sciences of the United States of America, the researchers surveyed more than 800 adult men regarding their sexual orientation, their gender expression, and three specific biomarkers: handedness, fraternal birth order, and existence (if any) of non-straight relatives.
The researchers — four from the University of Toronto and one from Memorial University of Newfoundland — found that having at least one older brother increased the likelihood of men not being straight by 14.8 percent and that being left-handed raised that probability by 34 percent.
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Related: Science says gay guys with older brothers are more likely to be big ol’ bottoms
“While the majority of both heterosexual and non-heterosexual men were grouped in the profile that did not have any biomarker, the three profiles associated with a biomarker were composed primarily of non-heterosexual men,” the researchers write in the study.
“Together, these findings suggest there are multiple distinct bio-developmental pathways influencing same-sex sexual orientation in men.”
Let’s hear it for the queer, southpaw little bros!
PLAYS WELL WITH OTHERS
Left handed and youngest of 4 boys and Gay!
TomG
No need for a study, I am the youngest brother and my partner of 30 years is left handed. I could have told them all of that.
Doctor Benway
So true.
That’s why i’m right handed and the oldest of 4 boys.
36glebe
And I’m ambidextrous (more right tho) & only child
JK 1984
I’m a youngest of three boys leftie. My husband is an oldest child right hander.
So not sure what to make of that hahaha.
Celtic
Means you can jack each other with either hand. 😀
River Runner
If you don’t believe the left-handed marker, just go to a gay bowling league…lefty little brother here..
Celtic
SO. Tell me: I had no older brother. I am right-handed. And I “knew” I “like men, especially their butts” at age FIVE. Now, when I was 5 the word “gay” meant nothing about sexual orientation. Yeah, I know. I’m old. Get over it! 🙂
kiriakis1
Why don’t you get over it?
Loki
Some people didn’t pay attention in Intro to Genetics. These are two distinct pathways to homosexual orientation in males. Handedness is gene linkage. Fraternal birth order is probably epigenetic. So declaring yourself a right-handed only child isn’t disproving anything.
With fraternal birth order, it’s likely that the mother’s womb reacts to the expression of the Y chromosome in the male fetus and this reaction accumulates over time. After each successive birth of male children, the chances for a gay male child increases.
Donston
The reasons behind whoever’s orientation/sexuality/general preferences is a weird thing to decipher. How we get to where we get to seems to be on a person by person basis. There does appear to be some physiological/DNA connections and patterns with some folks but not for others. Orientation more than likely is a mishmash of physiological, psychological, environmental and sense of gender, with some of those elements being more important to an individual’s orientation than for others.
Josh447
It’s all chemistry, unchangeable chemical makeup. All of it.
Donston
Josh447, so, you’re pretty much dismissing the idea of “fluidity”? What about people who claim they were inherently heterosexual, bisexual, homosexual for years and then their orientation, their attractions, arousals, passions shifted as time went on? Are they all lying? What about people who are really turned on by certain aspects associated with a gender but generally doesn’t have preferences toward that gender? Or even people claim to over time become grossed out by certain aspects of a gender that they were once turned on by? What about the romantic/emotional/relationship spectrum? The romantic, affection, emotional, relationship parts of who you are isn’t as much about inherent chemistry. Those things are much more connected to psychology. And even the sexual part can be much more about psychology than physiology.
Claiming everything is about chemistry and everything is unchangeable offers some extreme limitations, especially since while some patterns are more likely, none of the supposed patterns are very consistent.
Loki
“…does appear to be some physiological/DNA connections and patterns with some folks but not for others.”
Much like physics, the rules of biochemistry are the same for everyone.
Male homosexality is likely both polygenic (controlled by two or more genes) and epigenetic (genes are turned on or off due to the presence of certain environmental stimuli – antibodies produced by the mother in the placental environment).
Josh447
Donston,
The body is a collection of chemicals. If someone’s orientation shifts over life, it’s biological, chemical. When I say unchangeable, I mean it’s set at birth and will then flower over time. That flowering can include the “changes” of which you speak. But actually it is following a preset body program that includes modifications.
It’s all nature, chemical, no nurture. To say it’s nurture would mean one can control sexual orientation through outside sources which, like conversion “therapy” attempts, is impossible.
graphicjack
Check. Check. Check. Yes, I had a gay uncle. Yes, I am left handed. Yes, I am the youngest of five children and three boys. I am also a ginger and blue-eyed. I say I am basically a unicorn I have so many recessive biological traits.
Josh447
Well that’s pretty darn adorable.
Josh447
Youngest bi bro of two older straight bros no sisters. I am also right handed.
baggins435
Five boys and one girl in my family. Born from 1958 through 1973. The 3 oldest of us are gay. The oldest two are lefties. Everyone else in the family is straight and right handed. Our fraternal grandmother had lefty tendencies, but back then the teachers literally beat it out of you. No other known gay family, but considering the times, no one would have been out.
A previous job I worked had 100 people and at least 20 were lefties and 10 were gay/lesbian.
When I lived in Utah there was a family with 9 kids and 6 were gay or lesbian.
Loki
The number of older brothers is the key statistic. I believe having a gay older brother (or a gay twin) also increases the chances that the younger male siblings will also be gay. There is research that suggest (the genes for) male homosexuality might be linked to genes for fecundity in females.
WestLA90069
I’m the second of five children, but the only male. I’m right handed. However, my mother had a gay brother and a gay first cousin. As they said, “…multiple distinct bio-developmental pathways.”
gyntlgynt
I’m my father 7th child and my mother 2nd son,I’m left handed and I’m gay.
Brian
I had a friend years ago tell me a theory about the third child being gay. I’m the third of 4 boys, her gay uncle was the third child, her gay son is her only child, but is her ex husband’s third child. Completely anecdotal, of course, but this article reminded me of that.
Josh447
Third child here. Very interesting. And as they say, 3s a charm.
EliottlovesLucas
I tend to think most of these studies are junk science often disproven later. What people fail to grasp is tendency or more likely does not mean all or most. The fraternal birth order study is more accurate at predicting if a boy will grow up to be transgender. However scientist tend to group transwomen and gay men in the same category so you have to really follow and read the studies and discover what they actually say. In other words the fraternal affect is a predictor of transexualism in born male at birth children less of a predictor of homosexuality.
michel_banen
I’m the left handed little brother and yup – I’m gay. My older brother is left handed too but not gay. I’m not sure what differnce studies like these make though….
JessPH
Youngest of three boys but right-handed.
Aromaeus
I’m right handed and adopted. As far as I know I was the first boy and first child of my birth mother.
chris
Eldest brother – right handed and definitely not straight – these studies are open to being abused and exploited by bigots
Cam
It sounds like this study is just repeating the same information similar studies have been showing for over a decade now.
organicfood
Nice Post…
tripinnholiday87
I would like to thanks for this helpful and meaningful information.