The Warrior Who Carried Life

I read this book many years ago, but when I can remember some of the plot after more than 10 years then I know the book is a great read! The story is about a girl who is attacked savagely when she was young making her unable to have children. She participates in a magical ritual that turns her into a guy and she/he then becomes a strong warrior. As a warrior she/he protects those who are weak and falls in love. Eventually, the warrior becomes a woman again and has a baby. The story incorporates the idea of a tree of life and evil being in the form of a snake. Overall, I found it to be an excellent book that I would highly recommend to anyone that likes fantasy and action books!