While I'm sure some of the girls have a grade advantage during jump roping if they spent their entire childhood doing it - you'd pretty much eliminate all sports if you tried to find one someone didn't have an advantage in for the same reason.
Between my own school, teaching, and now my boys school I've been in schools for 35 years - jump roping has been part of the curriculum in every school I've been at. One of the districts even had a jump rope team - coed and taught by a man - that traveled and performed.