The other pay gap
We find lesbian women earn more than their heterosexual counterparts irrespective of marital status while gay men earn less than their married heterosexual counterparts but more than their cohabitating heterosexual counterparts. [...] differences in human capital accumulation (particularly education) are the main reason behind the observed wage advantages, while discrimination and occupational sorting play a minimal role at best.
The paper is here (free access), via George Borjas.
