It might or could be true, except for this:
There are countless numbers of former homosexuals. Or people who were not homosexual but in midlife at some point “found out” that they were.
Humans are much, much more than genes and chemicals.
Regarding those who overcome homosexuality, you have to remember that epigenetics also claims that methylation changes over the course of a lifetime.
How methylation over multiple generations finally results in a genetic change is still a question, but it's suspected that there is a process that does that.
I have no doubt the same Leftwingtards who want you to hire homosexual Mexican lawnboys will want you to make sure your pre-borns are tested for homosexuality so they may be killed.