... demonstrated in a recent paper for Family Research Council, studies based on four large, population-based, longitudinal data sets, drawn from such surveys, all demonstrate that significant change in each of the elements of sexual orientation is possible. In one survey of “same-sex attracted respondents,” up to 38 percent of men and 53 percent of women “changed to heterosexuality” in only a six-year period. [Source]
Most researchers prior to the 1970s believed, as many still do today, that homosexual attractions are primarily a developmental result of childhood experiences. There are some patterns that appear frequently in the life histories of those with same-sex attractions. These include poor bonding with the same-sex parent or peers, or having been a victim of child sexual abuse.
I'm old-school on this issue and will remain so until there's compelling evidence to change my mind. I do understand that epigenetics has an influence and that, that was not addressed in the linked article. However, epigenetics is something that can be changed in real time via changes in behavior.