Female player-coach duos are still a rarity in tennis, but they work — just ask Marta Kostyuk and Sandra Zaniewska Tennis How female tennis players and coaches figure out their sport and each other ...

There are only 13 women in the WTA Top 200 with a female coach, and four of them are the players mother. (AP Photo/Howard Fendrich) That didn't turn out to be a watershed moment for female coaches.

Last year was the 50th anniversary of Title IX, which has significantly opened the doors for female participation in school athletics. But when it comes to coaching, women continue to lag behind.