title: Extreme skewing of X chromosome inactivation in mothers of homosexual men.
abstract: Human sexual preference is a sexually dimorphic trait with a substantial genetic component. Linkage of male sexual orientation to markers on the X chromosome has been reported in some families. Here, we measured X chromosome inactivation ratios in 97 mothers of homosexual men and 103 age-matched control women without gay sons. The number of women with extreme skewing of X-inactivation was significantly higher in mothers of gay men (13/97=13%) compared to controls (4/103=4%) and increased in mothers with two or more gay sons (10/44=23%). Our findings support a role for the X chromosome in regulating sexual orientation in a subgroup of gay men.
authors.affiliation: Department of Human Genetics, University of California-Los Angeles, Los Angeles, CA, USA. sbocklandt@mednet.ucla.edu
authors.forename: Sven
authors.initials: S
authors.lastname: Bocklandt
authors.forename: Steve
authors.initials: S
authors.lastname: Horvath
authors.forename: Eric
authors.initials: E
authors.lastname: Vilain
authors.forename: Dean H
authors.initials: DH
authors.lastname: Hamer
mesh_terms: D016022:Case-Control Studies; D041321:Chromosomes, Human, X; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics; D018451:Homosexuality, Male / Q000235:genetics*; D006801:Humans; D008297:Male; D009035:Mothers; D011944:Receptors, Androgen / Q000235:genetics; D013223:Statistics as Topic; D049951:X Chromosome Inactivation
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1; D011944:Receptors, Androgen; C497683:FMR1 protein, human