How is a Dalai Lama chosen? And can it be a woman?

The 14th Dalai Lama is about 80 now. How will the next one be chosen or elected? Does the Dalai Lama himself decide, and has this already been decided? Are they, like the Catholics, 'voting' on candidates? Is it like the different sects take "turns", so for example now it's the Nyingmas turn to have the Dalai Lama? If someone is picked, can he refute? And is there any chance for the Tibetans to get a female Dalai Lama?