Scientists may have just discovered genes linked to homosexuality in the largest ever study into sexual orientation and genetics. Researchers examined the complete genome of more than 1,000 gay men and compared the data to the genomes of heterosexual men.

They found that the DNA tended to be different for gay and straight men, particularly when it came to the genes SLITRK5 and SLITRK6. SLITRK6 is fundamental in the development of the brain and is active in the hypothalamus, which is responsible for producing hormones.

Scientists have widely held that homosexuals are born with a “gay gene” and therefore do not choose their sexual orientation. This finding would further solidify that theory.

“Family and twin studies suggest that genes play a role in male sexual orientation,” reads the paper’s abstract, which was published in the journal Nature. “We conducted a genome-wide association study (GWAS) of male sexual orientation on a primarily European ancestry sample of 1,077 homosexual men and 1,231 heterosexual men using Affymetrix single nucleotide polymorphism (SNP) arrays. We identified several SNPs with p < 10−5, including regions of multiple supporting SNPs on chromosomes 13 (minimum p = 7.5 × 10−7) and 14 (p = 4.7 × 10−7). The genes nearest to these peaks have functions plausibly relevant to the development of sexual orientation. On chromosome 13, SLITRK6 is a neurodevelopmental gene mostly expressed in the diencephalon, which contains a region previously reported as differing in size in men by sexual orientation.”