Why do lesbians get paid more?

Eric Crampton blogs:

Says BoingBoing:

“Lesbians make more money than straight women (And nobody really knows why)”Really? Nobody? can think of a couple of explanations, pretty easily testable.

And Eric's theories:

First, and most importantly, maternity risk. If an employer expects a lesbian employee to be less likely to take maternity leave, and if maternity leave imposes costs on an employer, then the employer will be more likely to hire and to promote the lesbian over the straight woman. What evidence do we have? Petit's field experiment showing that maternity risk is responsible for a fair bit of women's lower average salaries.

Certainly possible.

Second, testosterone and negotiation strategies. Women, on average, are less aggressive in wage negotiations. If testosterone correlates with aggressiveness in salary negotiations, and some evidence suggests higher than average testosterone levels among lesbians as compared to heterosexual women (though that evidence is contested), then we've another candidate explanation.

I'd put money on the maternity risk variable. I'd only put money on the negotiations one at decent odds.

Funnily enough, my gut instinct is that a more aggressive negiotating stance would be the bigger contributor to the gap.

But really, if correcting for the observables reduces the wage gap between lesbians and heterosexual women from around 40% [the paper cites average hourly wages of $18.70 for lesbians and $13.34 for cohabiting non-lesbian females] to around 5%, odds are pretty high that there are a bunch of unobservables also correlated with job performance that aren't captured in the wage regression.

That's a pretty large pay gap.