“Conducted on identical twins,less than 10% of cases found both twins to be homosexuals.”
I find this interesting as the parental environment is a major influencing factor and both would be in the same environment.
True, but we should be careful not to oversimplify the idea of nurture being the prime factor when it comes to determining sexual orientation. It is likely to be a specific event or combination of events that causes the shift, rather than just a general environment growing up. Since even in the same household no two children’s experiences during childhood are the same, this would seem very plausible and the trigger could be something very innocuous or benign.