That has happened before.
“There is no published scientific evidence supporting the efficacy of 'reparative conversion therapy' as a treatment to change one's sexual orientation” the American Psychiatric Association has officially stated. "Clinical experience suggests that any person who seeks conversion therapy may be doing so because of social bias that has resulted in internalized homophobia, and that gay men and lesbians who have accepted their sexual orientation are better adjusted than those who have not done so."
Perhaps the most famous case study in the failure of reparative therapy is that of two founders of Exodus International in 1976, Michael Bussee and Gary Cooper, who worked to "convert" gay people for three years, until they fell in love and left Exodus in 1979. In 1982, they held a marriage ceremony and lived together until Cooper died nine years later. "The desires never go away," Bussee said. "After dealing with hundreds of people, I have not met one who went from gay to straight. Even if you manage to alter someone's sexual behavior, you cannot change their true sexual orientation."
Look at it in reverse. As a heterosexual person I cannot imagine having to undergo some sort of therapy to convert me to homosexual. Moreover I cannot even imagine it working. Homosexuality is certainly not a choice. Moreover, given the hatred, the condemnation and the persecution so prevalent in society, I cannot imagine anyone making that choice.