In Germany, at least three quarters of nurses are women from what I would guess. So if you actually want to take a bet, betting on them being a woman makes you at least three times as likely to be correct as other bets.

Edit: first source I could find says that in 2007, 86% of nurses were women in Germany:

https://de.wikipedia.org/wiki/Krankenpfleger#Besch%C3%A4ftig...