LOL! Mohini is a female gender, avatar of Vishnu. Vishnu is the male manifestation of supreme being. Shiva another male manifestation of the God or himself a god of destruction and many more. You don't understand it when you believe God is male.
Also, sexuality is not by birth. Once you become mature, some people exhibit sexual attraction towards their own gender. It maybe hormonal but who are we to judge what's considered normal. A few centuries back marrying and having sex with little girls was considered normal. Now it's pedophilia.