Over the last decade, studies of twins have provided some of the
strongest evidence that “Our genes do not make us do it”. If you take pairs of identical twins in which one twin is homosexual, the identical co-twin is usually not homosexual. That means, given that identical twins are always genetically identical, homosexuality cannot be genetically dictated. No-one is born gay. The predominant things that create homosexuality in one identical twin and not in the other have to be post-birth factors.