This time, it's chess players.
This has remarkable implications for female wage equality. If women aren't receiving equal wages for what looks like the same job, it very well could have something to do with women having taken less risk in their careers, which wouldn't show up in statistics easily but would be reflected in standing within the company.
Of course, there are other reasons for the gender gap in earnings for identical job titles. Assuming that men and women in a position have the same level of experience - not necessarily true, given things like childbirth - it's also possible that companies assign projects differentially to women or pay women differentially because of the risk of possible absence from work due to childbirth or motherhood.
Sexism is a possible explanation, as well, that needs little exposition from me.