This is a question many people are trying to find the answer to.
The evidence suggests that there is a genetic and an environmental element to it. Homosexuality and bisexuality have been recorded throughout history and are also widespread throughout the animal kingdom.
I’m not really sure about using the word “choice”. I don’t think many people consciously choose who they are attracted to – I think various subconscious, biological and environmental factors influence our sexuality.
being straight myself it’s a bit hard for me to answer this one but I would definitely say that ‘choice’ is the wrong word. Some people just are gay and are naturally attracted to others of the same sex.