Until I can give a randomized sample of blood vials, some number of them homosexual, and a technician can identify who is gay or not 80%+ of the time, the answer is unknown and very likely "no."

The current philosophical argument of being born gay can literally be used to justify any behavior you want. Do you like stealing? You were born to steal. Like murdering? Born to kill. Like fucking animals? Born attraction to dogs. And how can anyone argue otherwise?