How the hell do straight people know if people are born gay or not?

Honestly, what do straight people know anyway? How do you know if someone is born gay or not? Do you honestly think that someone WANTS to be gay in a world where gays are discriminated and executed? Why would gay people go through all the **** they have to put up through from bigots and religious ideologues and still make it "their choice"? Nobody wants to be discriminated or punished. People want to be happy. If ity was a choice, why would people choose that way and become unhappy from all the discrimination in the world????