Matthew Vines writes in his book as follows:
As a lawyer, my dad weighed the evidence for the possibility of orientation change. Pointing to Matt. 19:26, he reminded me that all things are possible with God. Yet after reading a fair amount about "ex-gay" ministries, he realized that none of the evidence seemed to show God was changing gay people's sexual orientation (God and the Gay Christian, p. 10).
A controversial Christian ministry devoted to changing people "affected
by homosexuality" announced in April of 2014 that it was shutting its doors
after operating for more than three decades. The announcement by Exodus International
came during its religious conference in Irvine and after its President Alan
Chambers apologized to members of the gay community for "years of undue
judgment by the organization and the Christian Church as a whole." (http://jonathanmerritt.religionnews.com/2014/04/22/
In October of 2011, John Smid, the former director of Love in Action, the country's
oldest and largest ex-gay ministry, acknowledged on his blog that, contrary
to the claims of the movement he represented for decades, gay people cannot
become straight. "I've never met a man who experienced a change from homosexual
to heterosexual," he wrote. He himself certainly has not. Evangelicals
used to insist that "change is possible," says Warren Throckmorton,
a Grove City College psychology professor once associated with the ex-gay movement.
"The new paradigm, I believe, is no, it doesn't look like that works, and
so you go with it, you accept it, and you try to make the best life you can
in congruence with the rest of your beliefs," he says (http://www.thedailybeast.com/articles/2011/10/13/ex-gay-leader-john-smid-s-about-face.html).