If you could change the gender of 3 anime characters, which ones would you pick?

Rules:

1. No futa or other 2 gender. One or the other for this people.

2. They can either be aware of the change or have been like that from the beginning. (Personally I'd like to see Vegeta's face when he hits Super Saiyan five and suddenly turns into a girl)

3. Tell us how the change would affect the story and why you picked it.