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Post Pride "Science": Got older brothers? Move to URUGUAY, do not pass go!

Boss Hog

TRIBE Member
Having An Older Brother Raises A Male's Chances Of Being Gay

Having An Older Brother Raises A Male's Chances Of Being Gay
Main Category: Public Health News
Article Date: 26 Jun 2006 - 11:00am (PDT)

A male is more likely to be gay if he has an older brother, the likelihood grows the more older brothers he has. The percentage of gay males is estimated to be around 3%, this probability can go up to 5% for males with several older brothers, say researchers from Brock University, St. Catharines, Canada.

The researchers are certain there is a biological basis for sexual orientation - in other words, there is a prenatal effect. It is not a case of older brothers having a psychological effect on the male baby after it is born. Males with older stepbrothers, or adopted brothers, are not more likely to be gay, only males with blood brothers. The scientists say the effect has to be through the mother, the only link between them.

You can read about this study in the Proceedings of the National Academy of Sciences.

Previous studies have shown a link between male homosexuality and the number of older brothers. This study is the first one to factor out social and environmental effects.

Study leader, Anthony Bogaert, and team examined four groups of men - 944 males. They looked at how many male and female siblings they had, whether they were blood related and lived in the same house when they grew up. The also looked at whether the men had been adopted.

They found that males with one older blood brother were more likely to be gay than males with no older brother(s). The more older brothers a male had the higher his chances of being gay. They said the likelihood had the same increase when blood brothers were raised in different households.

The team stressed that even with several older brothers, the chances of a male being heterosexual is 95%. 97% of all males are heterosexual.

Only males who had an older brother from the same mother had a higher chance of being gay, said the researchers.

The researchers said the environment the male was brought up in makes no difference at all. The only link is that the older brother(s) shared the same womb.

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TRIBE Member
From the academic powerhouse that is Brock:

Men with older brothers more likely to be gay

By RANDOLPH E. SCHMID, AP Science Writer1 hour, 3 minutes ago

Men who have several older brothers have an increased chance of being gay, researchers say, a finding that adds weight to the idea that sexual orientation has a physical basis.

The increase was seen in men with older brothers from the same mother — whether they were raised together or not — but not those who had adopted or stepbrothers who were older.

"It's likely to be a prenatal effect," said Anthony F. Bogaert of Brock University in St. Catharines, Canada, who did the research. "This and other studies suggest that there is probably a biological basis" for homosexuality.

Bogaert studied four groups of Canadian men, a total of 944 people, analyzing the number of brothers and sisters each had, whether or not they lived with those siblings and whether the siblings were related by blood or adopted.

His findings are reported in a paper appearing in Tuesday's issue of Proceedings of the National Academy of Sciences.

S. Marc Breedlove, a professor in the neuroscience and psychology department of Michigan State University, said the finding "absolutely" confirms a physical basis.

"Anybody's first guess would have been that the older brothers were having an effect socially, but this data doesn't support that," Breedlove said in a telephone interview.

The only link between the brothers is the mother and so the effect has to be through the mother, especially since stepbrothers didn't have the effect, said Breedlove, who was not part of the research.

Tim Dailey, a senior fellow at the conservative Center for Marriage and Family Studies disagreed.

"We don't believe that there's any biological basis for homosexuality," Dailey said. "We feel the causes are complex but are deeply rooted in early childhood development."

There have been a number of attempts to establish a physical basis "and in every case the alleged findings have been severely challenged and questioned," he said.

"If it is indeed genetically based it is difficult to see how it could have survived in the gene pool over a period of time," Dailey added.

Bogaert said the increase can be detected with one older brother and becomes stronger with three or four or more.

But, he added, this needs to be looked at in context of the overall rate of homosexuality in men, which he suggested is about 3 percent. With several older brothers the rate may increase from 3 percent to 5 percent, he said, but that still means 95 percent of men with several older brothers are heterosexual.

The effect of birth order on male homosexuality has been reported previously but Bogaert's work is the first designed to rule out social or environmental effects.

Bogaert said he concluded the effect was biological by comparing men with biological brothers to those with brothers to whom they were not biologically related.

The increase in the likelihood of being gay was seen only in those whose brothers had the same mothers, whether they were raised together or not, he said.

Men raised with several older step- or adopted brothers do not have an increased chance of being gay.

"So what that means is that the environment a person is raised in really makes not much difference," he said.

What makes a difference, he said, is having older brothers who shared the same womb and gestational experience, suggesting the difference is because of "some sort of prenatal factor."

One possibility, he suggests, is a maternal immune response to succeeding male fetuses. The mother may react to a male fetus as foreign, but not to a female fetus because the mother is also female.

It might be like the maternal immune response that can occur when a mother has Rh-negative blood but her fetus has Rh-positive blood. Without treatment, the mother can develop antibodies that may attack the fetus during future pregnancies.

Whether that's what is happening remains to be seen, but it is a provocative hypothesis, said a commentary by Breedlove, David A. Puts and Cynthia L. Jordan, all of Michigan State.

The research was funded by the Social Sciences and Humanities Research Council of Canada.

I also enjoyed the fact that someone named "Breedlove" was asked to comment on prenatal sexual orientation research


TRIBE Member
I saw something on TV about this study a while ago. They went further to hypothesize it has something to do with hormone levels in the mother changing after carrying a boy.
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TRIBE Member
My article's better too!

And the bold texting of relevant snippets? Like the crowning tiara!

Clearly this kind of fabolousness is rooted in the fact that this thread was born 5 minutes after Boss Hog's.


TRIBE Member
I'm an only child and gay (my poor mother) figure that out MR. Science.

I do know 2 families which have 3 boys each, the youngest being gay in both families.
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TRIBE Member
yes, i will have to go with deep on the title, plus he has the whole 'bold' thing going on.

deep's post is way gayer.


TRIBE Member
I read the article this morning. Clearly you are not ready for this jelly girlfriend.

*z snaps all around the world, sashaying down the runway*
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TRIBE Member
Did the threads get combined? Does this mean the thread is now bisexual?


(I hear that's how it begins)

Boss Hog

TRIBE Member
I want to know what's up with parents who have more than one gay child. What are the chances of having a gay son and gay daughter? It seems more common than I realized.


TRIBE Member
Well if the son is a twink and the daughter is butch then it's all the same isn't it?


Boss Hog

TRIBE Member
wtf I just realized now what's going on with the merged posts.


I get credit for deep's smrtness
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TRIBE Member
boss hog has an older brother

I am an older brother

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