Why do women who have enormous talent stop their professional lives after marriage?

Its a personal decision one would say, but do they even realize the consequences the decision they are making would have on other people or a country as a whole? I have been a big advocate of, women should not stop working after marriage (at least the most talented ones). There are several examples in our country where women take such a drastic decision. They are not at all doing any justice to the immense talent they have. Most recently we have heard about Sania Mirza. After winning so many titles in women's tennis she has decided to stop playing professional tennis, after marriage that is. She had immerged as a single Indian women who had completely changed the attitude of Indian tennis lovers for women's tennis. And following her example are a lot more Indian women who were talented and were fearing to make it to the big scene, but for their role model Sania. Just being 22, she still has a lot of tennis left in her. India needs her and lot more like her. It's really painful to see immensely talented women like her taking such a drastic step. God knows now who will fill the void created by her absence. Even in my close circle I have seen extreamly talented women making such a decision. It's their life after all, but they dont understand the injustice they are doing to their talent.