Here's an interesting, offensive article. Apparently female tennis players are more likely to make unforced errors on important points than other points. This is interesting, but I'm more interested in the fact that men are as likely to make unforced errors on every point.
When pundits talk about big match temperament (BMT) I usually take it as a sign of a lack of professionalism rather than a special ability. If someone is capable of "stepping it up" in the big moments he's capable of stepping it up every moment but doesn't for some reason. I think that some players are just very good and can afford to slack off half the time, so it doesn't surprise me that players with “BMT” are often great players because they’re the ones who get away with it.
If my theory is true then BMT isn’t actually something to be proud of.
As athletes get paid more, competition gets stiffer and players become more professional. There’s a big incentive to play your best on every point. It looks like this has happened for male player. Maybe women’s tennis just isn’t competitive enough.
I’m not sure why both men and women play more defensively on big points though.