Lesbians may not need to behave differently to be treated differently. They could face positive discrimination, if employers promote them on the assumption that they will not have children and so devote more time to work than straight colleagues. A study Ms Klawitter published in 2011 found that gay men working in the public sector suffered a smaller penalty than those in the private sector, whereas lesbians enjoyed a premium in the private sector but none in the public sector. One interpretation could be that discrimination of all sorts is more fiercely policed in government offices, dampening prejudice against gay men and in favour of gay women.
Lesbians’ higher earnings could also be a function of the gender of their partner. Men earn more than women, straight or gay; lesbians, deprived of the extra earnings a male partner would bring, may work harder to compensate. At any rate, they work more hours per day and weeks per year than straight women, on average (see chart). Over time this could translate into more experience and better chances of promotion. There is a clue in a paper from Nasser Daneshvary, C. Jeffrey Waddoups and Bradley Wimmer of the University of Nevada, which finds that lesbians who have previously been married to men receive a smaller premium than those who have not.
Finally, it could be that in same-sex couples women do not feel obliged to do as much childcare or housework, giving them more freedom to fulfil their potential in the workplace. Lesbian couples tend to work more equal hours, even when they have children, and several studies find that same-sex households share chores more evenly than heterosexual ones.
Whatever the reason for lesbians’ wage premium, it does not make them a privileged group. There is evidence that they face discrimination in hiring relative to straight women, even though their pay is better. Poverty rates among lesbian couples are 7.9%, compared with 6.6% among heterosexual ones. And for boosting earnings, as in so many realms, nothing beats being a straight, white, married man.