I don't believe a person can be gay or lesbian. Even if they exist, they are the worst human race in in the world. How a male or female is willing to have sex with another male or female. That's why world was made with both male and female. Otherwise, world would have been made only with male or female. It is natural that every person has an attraction towards his or her opposite gender. So when a person acts like he or she is a gay or lesbian, he is absolutely fake. Remember, if the nature would really like gay or lesbian, there would be no existence of human race till now in the world.
Why would anyone choose to have sex with the same gender in places where they can be killed just because of that? Why homosexuality exists in more than 1500 animal species?
Scientific evidence shows that the sexual orientation is likely predetermined during gestation, so it cannot be a decision.
Nobody forces you to have sex with people of your own gender, and I think you should not worry about who other people have sex with.
Humanity cannot produce and distribute enough food for everyone, and this issue will be more and more important as population grows and natural resources gets exhausted. Homosexuality decreases population growth so it has a positive effect. Homosexuality could be a natural mechanism for preventing overpopulation.