Gender differences in productivity, if any, that are unobserved to researchers may produce an omitted variable bias in gender gap studies. Finding a subpopulation with less acute differences in unobserved characteristics would allow this concern to be addressed.
This paper shows that gays and lesbians are one such interesting group-for the intra-household division of labor and its effects on market productivity cannot be sex-determined in this subpopulation. Indeed, there are substantial intra-household variations in labor market outcomes and other characteristics; the patterns and magnitudes are similar to different-sex households.
Simultaneously, the gender wage gap between gays and lesbians is much smaller than in the heterosexual population; in specifications that control for geographic location it is near zero. These findings suggest that the intra-household division of labor is an important factor driving gender differences in labor market outcomes.
Such an interpretation is consistent with recent studies that control for productivity.