Are Younger Brothers More Likely to Be Gay? | Psychology Today

Contents:

• MEN WH OLR BROTHERS ARE MORE LIKELY TO BE GAY, STUDY SUGGTS
• MEN WH OLR BROTHERS MORE LIKELY TO BE GAY
• HOW TO TELL IF YOUR SON IS GAY
• A PROBABILY SAMPLE OF GAY MAL
• GAY GEICSMOST OF BELIEVE THAT WE WERE BORN THAT WAY, BUT IS SEXUAL ORIENTATN OUR DNA? JV CHAMARY GO SEARCH OF THE GAY GENEJV CHAMARYPUBLISHED: MAY 31, 2009 AT 11:00 PMGAY GEICS
• WE MAY KNOW WHY YOUNGER BROTHERS ARE MORE LIKELY TO BE GAY
• ARE YOUNGER BROTHERS MORE LIKELY TO BE GAY?

MEN WH OLR BROTHERS ARE MORE LIKELY TO BE GAY, STUDY SUGGTS

How Olr Brothers Influence HomosexualyHomosexualy might be partly driven by a mother’s immune rponse to her male fet—which creas wh each son she MacGregor / RtersHere’s what we know: Homosexualy is normal. Between 2 and 11 percent of human adults report experiencg some homosexual feelgs, though the figure vari wily pendg on the survey. Homosexualy exists across cultur and even throughout the animal kgdom, as the thors of a mammoth new review paper on homosexualy wre.

Female Japane maqu will even pete tersexually wh mal for exclive accs to female sexual ’s what we don’t know: What, specifilly, someone to bee gay, straight, or somethg between. Part of the explanatn is geic, but bee most intil tws of gay people are straight, heredy don’t expla “why” qutn is important bee “there is a strong rrelatn between beliefs about the origs of sexual orientatn and tolerance of non-heterosexualy, ” acrdg to the report thors, who are om seven universi spanng the globe. (When Atlantic ntributor Chandler Burr proposed his 1996 book, A Separate Creatn, that people are born gay, Southern Baptists lled to boytt Disney films and parks prott agast the publisher, Disney subsidiary Hypern.

) It shouldn’t matter whether people “choose” to be gay, but polilly, do—at least for of the most nsistent environmental explanatns for homosexualy is lled the “aternal birth orr effect. Studi have found that a man whout olr brothers has about a 2 percent chance of beg gay, but one wh four olr brothers has a 6 percent chance.

MEN WH OLR BROTHERS MORE LIKELY TO BE GAY

Average prevalence 2013 (Sav-Williams and Vrangalova)Acrdg to the report, Blanchard now plans to tt mothers of gay and straight men for the prence of the antibodi.

If proved out, fetal birth orr uld do a lot to fill the missg explanatns for homosexualy. But gaps will rema, such as why some firstborn sons are gay, why some intil tws of gay sons are straight, and why women are gay, to name jt a review-paper thors do le out one explanatn for homosexualy, however: That tolerance for gay people enurag more people to bee gay.

“Homosexual orientatn do not crease equency wh social tolerance, although s exprsn ( behavr and open intifitn) may do so, ” they reasong—that a tolerant society somehow enurag homosexualy to flourish—has been ed to support anti-gay legislatn Uganda, Rsia, and elsewhere. Men wh olr brothers are more likely to be gay, acrdg to a study published Wednday the journal Proceedgs of the Royal Society B.

HOW TO TELL IF YOUR SON IS GAY

This new report builds upon prev rearch regardg male birth orr and homosexualy, though there is still no cisive ncln as to why there’s a lk between the cross-analyzg data om 10 scientific studi wh more than 5, 000 subjects, rearchers found that men wh olr brothers were 38 percent more likely to intify as gay.

A PROBABILY SAMPLE OF GAY MAL

”The study, which pared the probabily of the youngt brother a two-son fay beg gay as pared to the olst son, did not clu female subjects, as prev rearch has tablished that women do not fluence the sexual orientatn of their younger siblgs, acrdg to this study did not terme a ncrete reason for the rrelatn between a man havg an olr brother and intifyg as gay, Blanchard said that “pots toward the need for more rearch on the 'maternal immune hypothis'” — a theory Blanchard troduced 1996 that suggts that a mother is exposed to “male-specific substanc” durg pregnancy wh or the birth of a son. Acrdg to proponents of the theory, the mother’s immune rponse is changed durg the pregnancy of a boy, creasg the likelihood that a subsequent male child would be gay. Specifilly, many aspects of the velopment of homosexualy (both the male and female varieti) are not as well unrstood as they should be to make some of the claims that many people felt nfint exprsg.

There's a lot to discs regardg the rults of the paper (Skorska et al, 2016): The rearchers were examg the possibily that a maternal immune rponse might play a key role the velopment of a homosexual orientatn mal.

Effectively, then, the mother's immune system would (sometim) treat certa male protes produced by the fet as a foreign pathogen and attempt to attack , rultg out that uld clu a homosexual orientatn, but also fetal loss if the reactn was strong enough (i. Already there is a lot to like about this hypothis on a theoretil level, as don't pos any hidn adaptive benefs for a homosexual orientatn (as such proposed benefs have not received sound empiril support historilly).

GAY GEICSMOST OF BELIEVE THAT WE WERE BORN THAT WAY, BUT IS SEXUAL ORIENTATN OUR DNA? JV CHAMARY GO SEARCH OF THE GAY GENEJV CHAMARYPUBLISHED: MAY 31, 2009 AT 11:00 PMGAY GEICS

The rearchers reced approximately 130 mothers and classified them on the basis of what kd of children they had: those who had at least 1 gay son (n = 54), and those who only had heterosexual sons (n = 72). The mothers were then classified further to one of five groups: those wh gay male only-children (n = 8), those wh gay male offsprg that had no olr brothers (n = 23), those wh gay male offsprg wh olr brothers (n = 23), those wh heterosexual male only-children (n = 11), and those wh heterosexual male offsprg wh siblgs (n = 61).

As predicted, the average number of fetal loss were higher the first group (mothers of gay male only-children; M = 1. When nsired terms of the rat of misrriag to live to births, a siar picture emerged: mothers of gay male only-children reported more misrriag to live births (M = 1. As birth weight tends to crease over succsive pregnanci, the parisons were limed to first live-born sons only (n = 63); this left 4 gay male only-children, 7 gay mal wh no olr brothers, 14 heterosexual mal wh gay younger brothers, 10 heterosexual male only-children, and 28 heterosexual mal wh siblgs.

The rults mirrored those of the fetal-loss data: mothers of gay male only-children tend to give birth to fants that weighed signifintly ls (M = 2970 grams), than all other groups (d = 1. In sum, then, mothers of gay male only-children tend to have a greater number of misrriag and give birth to signifintly lighter offsprg than mothers of other kds.

WE MAY KNOW WHY YOUNGER BROTHERS ARE MORE LIKELY TO BE GAY

While 's important to not get rried away wh this fdg given the relatively small sample size (I wouldn't put too much stock an N of 8), there is some suggtive evince here worth pursug further that somethg is atypil fetal velopment the se of gay male offsprg.

The first qutn that to md is why this effect seemed to be specific to gay male only-children, rather than gay male children wh siblgs? Skorska et al (2016) pos that this might have somethg to do wh some mothers showg a greater immune rponse agast male offsprg, rultg more fetal loss, the rult beg that such mothers are both ls likely to have any children at all and more likely to have gay male children particular.

In other words, mothers wh gay male offsprg should be expected to have proportnately more female children owg to a greater male fetal loss.

ARE YOUNGER BROTHERS MORE LIKELY TO BE GAY?

If mothers of gay men do not tend to have a greater rat of female-to-male offsprg, this would st some doubt on the explanatn (and, sce the only data I've heard reports that gay men tend to have more olr brothers, seems they would have noticed the sister pot by now if existed). On the other hand, if this is a more general immune reactn agast fetal bodi, regardls of their sex, we would not expect such a pattern ( might also predict that mothers takg immunosupprsants would be ls likely to have gay offsprg/misrry, but thgs are unlikely to be that simple owg to the fact that other effects would rult too).

Intil male tws—those who share both their geics and maternal fetal environment—only show a nrdance rate of homosexualy of approximately 30%. As far as I'm aware, homosexual preferenc (not the ocsnal behavr) do not appear to be well documented nonhuman speci; the only exceptn I'm aware of is Rams.