The best they can do is teach them that they are as good as the girl who sits next to them in history class. It may even plant a seed which grows into a doubt about one's potential as a player. I take home a trophy in the girl's tournament, but not in the big tourneys when I play boys, too. That's one more for the Girl's Club. On a whole I think a system which encourages and rewards women for playing against each other works against improving women as chess players.
People lament that women's ratings lag so far behind men's.
To become a stronger player and to get more points you have to play stronger opponents. At this point in time, that means playing men, taking their points and earning their titles.