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

Contents:

• YOUR GOOD HEALTH: WHY IS ONE ‘INTIL’ TW GAY, THE OTHER STRAIGHT?
• 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
• ARE YOUNGER BROTHERS MORE LIKELY TO BE GAY?
• GAY MEN TW STUDY

YOUR GOOD HEALTH: WHY IS ONE ‘INTIL’ TW GAY, THE OTHER STRAIGHT?

Tw pairs which at least one tw is homosexual were soliced through announcements the gay prs and personal referrals om 1980 to the prent. Two sets ntaed a pair of monozygotic tws nrdant for sexual orientatn wh the third triplet dizygotic and disrdant for homosexual orientatn.

In a study where scientists looked at the sexual aroal patterns of intil tws wh different sexuali—specifilly, where one was gay and the other was straight—they found that gay tws monstrated more genal aroal rponse to same-sex imag, whereas straight tws monstrated more aroal rponse to oppose-sex imag [2].

In theory, this means two people uld rry “gay gen, ” but both of them wouldn’t necsarily be gay pendg on certa environmental factors. Studi have shown that intil tws, if one tw is gay (the term “homosexual” is ed clil studi but is nsired offensive, so I won’t e further), then 30 per cent to 66 per cent of the intil tws also will be gay.

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

However, an adopted siblg of a gay person is also more likely to be gay (11 per cent one study), suggtg that the faial environment also plays a signifint role. The search for ‘gay gen’ go back to 1993, when a US team led by Dr Dean Hamer scribed a regn of DNA loted on the X chromosome lled Xq28. “Conservative, right-wg people hated bee they felt that was sayg that beg gay is like beg black, that was -born, that would somehow ‘exce’ gay people or give them more rights, ” says Hamer.

“On the other hand, gay people hated too bee, at that time, there were fears that the disvery would be mised to abort gay babi and wipe gay people off the face of the Earth.

Although the fears rema, recent years the search for ‘gay gen’ has bee more accepted by the gay muny, no small part bee a blogil explanatn wouldunrme arguments that beg gay is a social or liftyle choice.

ARE YOUNGER BROTHERS MORE LIKELY TO BE GAY?

For stance, intil tw brothers (siblgs rived om the same fertilised egg) are more likely to both be gay than aternal tws (tws that velop om separate eggs). Now chief of the gene stcture and regulatn sectn at the US Natnal Cancer Instute, his study revealed a cur pattern: gay men tend to have more gay uncl and gay male s on their mother’s si of the fay than on their father’s. To track down the DNA regn lked to the gay tra, Hamer ed a technique lled ‘lkage mappg’, an approach that lets geicists fd a gene even when they don’t know what do or where ’s loted.

Lkage mappg works bee close relativ like brothers share not only a particular tra, such as homosexualy, but also the gen unrlyg the tra. So, if you study many pairs of gay brothers and fd a DNA regn that’s the same more than 50 per cent of s, ’s likely to be lked to homosexualy.

Asi om a few superficial differenc (among them penis and rg-fger length – both longer homosexuals), gay and straight men’s bodi appear the same. The exceptn is homosexual men’s bras, which show remarkable siari to the bras of heterosexual women, suggtg that sexual orientatn pends on the effect hormon have on the velopg bra.

GAY MEN TW STUDY

In 1996 Blanchard and Profsor Tony Bogaert revealed a peculiar phenomenon: the more olr brothers a boy has, the greater their chanc of beg homosexual.

Blanchard believ that homosexualy is “100 per cent blogil”, and timat that the aternal birth orr effect acunts for 15-30 per cent of gay men the populatn.