Actually the brain has been shown to be neuroplastic and can change on its own. If anything "makes" people gay or transgender it's likely testosterone or estrogen imbalances which can be correct through natural means.Sexuality isn't a choice, it's hard wired into the brain's structure. Doctors in Sweden have shown that the structure of gay female brains is the same of what it is in straight males, and the structure of gay male brains is the same as what straight females have.
Homosexuality in the Brain | Brain Blogger
So, the only way to "cure" someone of being gay, is to basically go in, restructure the brain, and they will be straight.
Only problem is, we don't have anywhere near the technology to do that, and even if we did, who would pay for something that might potentially erase you and replace you with another version?
There is absolutely no evidence that can be done. But you are welcome to believe whatever you want, despite the lack of evidence.