Looks like Lady Gaga was right: gay people really are born that way. The largest ever study of gay brothers has shown the "strongest evidence yet" that being gay is genetically determined, New Scientist reports. The discovery adds to a long-running debate that homosexuality is genetically linked and not a matter of choice.

Researchers analysed blood and saliva samples from 409 pairs of brothers (including non-identical twins) over a period of five years, looking for shared locations of genetic markers called single nucleotide polymorphisms (SNPs). They found found five SNPs commonly shared by the gay men, all clustered in two distinct locations on separate chromosomes. 

Alan Sanfers, who led the study, said that the discovery "erodes the notion that sexual orientation is a choice". He cautioned that scientists have yet to zero in on which specific genes contribute to sexual orientation, stressing that complex traits like sexuality are the product of multiple environmental and genetic factors. 

But others have hailed the find, which verifies a 1993 study by the US National Institutes of Health that was the first to indicate that homosexuality was biologically determined as opposed a lifestyle choice.   

"This study knocks another nail into the coffin of the 'chosen lifestyle' theory of homosexuality," neuroscientist Simon LeVay said. "Yes, we have a choice in life, to be ourselves or to conform to someone else's idea of normality, but being straight, bisexual or gay, or none of these, is a central part of who we are, thanks in part to the DNA we were born with."

(h/t HUH)