I was being kind in saying the evidence is mixed. It is my perception that the majority of those who identify as homosexual did not choose to be attracted to the same-sex; they simply are and always have been. For many in my generation (I'm 50), that meant living 'in the closet' and hiding who they really were. I suspect there is a small minority whose preferences may be more fluid and choose to live either a heterosexual or homosexual life. But, I find it laughable to the point of scorn for someone to suggest that your average heterosexual can be 'recruited' into homosexuality; it would go against their very nature, just as those who are homosexual who were forced to live a hetero life were living against their nature.
Nevertheless, my comment was not made in a vacuum and was influenced by the many posts made by this same individual which are decidedly hostile to our gay brothers and sisters.