We teach most women at a very young age to sit "ladylike" or some may say "sit like a lady". This means sitting with legs crossed or closed together. Take a look how this story plays out.
This can be an ugly thing to her body when you factor in pressure over time. Take a look around a waiting room and you will see most women sitting with legs together or crossed and men sitting with legs wide and feet outward. Wait, take another look around at women standing vs men standing. Women tend to stand with feet close together and men wider and apart.
Sitting ladylike leads to a tight IT band (runs from outside pelvis-hip to tibia-lower leg). Over time this tight IT band will lead to increased hip joint pressure causing a wearing of the hip joint. Add more time and pretty soon she will have a worn out joint and someone wants to give her a total hip replacement.
Let me have you take one more look around and see what this pressure over time does to women. A young woman has a wiggle to her walk, you can see her hips sway side to side with each step. An older woman's hips don't sway at all because her IT band is so tight that her feet have gradually gotten closer and closer together. This leads to a narrow base of support which means a much higher risk of falling. Let's think about the cause and not just focus on the stretching because if I take this patient and stretch for an hour but let her sit crossed legged for 8 hours a day I will lose. Remember a bad habit beats me over time, everytime because pressure over time wins.