Your willful, commonsense and entirely logical statement may cause you to be prosecuted under Hate Crime statutes.
Why are scientists willing to pollute the species by perpetuating a genetic defect?
Because they are able to get grant money to do it, journals will publish their white papers on the subject and provide subsequent career enhancement, and they get invited to all of the 'right' cocktail parties.
Isn’t there any ethics against that?
Ethics are politically-incorrect.
For all we know homosexuality is on the Darwinian downside and will vanish in the future.
It would indeed vanish a whole lot faster if it were not for the fact that it's being propped up by Governments and sympathetic "scientists".
It is not genetic. If it was then identical twins would always both be gay 100% of the time. They are not. If one is gay, there’s a 50% chance the other will be. The fact they are not 100% of the time, but a much lower 50% of the time, proves it is not merely genetic. Plus self testimony from lesbians and gays who admit making a conscious choice to be a homosexual.