Anyway back on subject...

Sexual identity is choice. It's like choosing Jif or Peter Pan peanut butter.
The actual behavior that alot of times accompanies this identity is learned.
Example:

There are gay males that try to act and sound like women. They like males and try to imitate a female.

In every one's life there has been an instance where some form of homosexuality has either in a small or big way crossed your path. You either rolled with it or you didn't. Plus what about bisexuals?