It will not be long, and there will be a test to detect the epigenetic structure that causes a male to be gay, with a high degree of accuracy. Though it may be true, that many epigenetically gay males, may chose to live a traditional heterosexual role, that does not change epigenetics. Most gays who have heterosexual relations, will not be able to perform them for an extended period without experiencing sexual dysfunction, as would a heterosexual male not be able to sustain a gay relationship. Eventually, the epigenetic coding will become apparent to the individual.
Now, the question is this: If you knew that your unborn male child, would have a very high probability of only being able to sustain a same gender relationship, would you chose to abort the child. If you say, Yes -- then you would, please explain your reasoning to chose abortion knowing that you wanted to know if your unborn male child could be gay, before he was born.