Ken Blackwell, tapped last week by President-elect Donald Trump to head domestic policy during the businessman’s transition to the White House, has made anti-LGBT statements for years. Among them: Homosexuality is a sin, and gay people, just like petty thieves and fire-setters, can be rehabilitated.

The former Cincinnati mayor has long endorsed a controversial mental health practice known as conversion therapy or reparative therapy. The goal is to cure a person of his or her homosexuality, and in the case of transgender people, to reaffirm the gender into which they were born.

In the past, treatments have included everything from inducing vomiting to using mild electric shock while patients viewed homoerotic images. Since the 1990s, however, the therapy has been denounced by many medical and scientific societies and even outlawed in a handful of states. In 2015, the Obama administration expressed disapproval of the practice after Leelah Alcorn, a 17-year-old transgender teen in Ohio, took her life after being forced by her parents to undergo conversion counseling.

While Blackwell will be overseeing a wide swath of domestic issues facing the new administration, one big question facing the LGBT community is whether a Trump administration will promote the therapy.

Two years ago, in a radio interview with Tony Perkins, the president of the Family Research Council, Blackwell appeared to blame the deaths of six individuals in a 2014 mass shooting in Isla Vista, Calif., on the LGBT rights movement, saying it undermined “natural marriage.”

“When these fundamental institutions are attacked and destroyed and weakened and abandoned,” said Blackwell, a senior fellow at the Family Research Council, “you get what we are now seeing, and that is a flood of these disturbed people in our society that are causing great pain.”

In an unsuccessful gubernatorial bid in 2006, the former Ohio secretary of state claimed that being gay was a “choice” that could be “changed.”

“I think it’s a transgression against God’s law,” he told the Columbus Dispatch at the time. “And I think you make good choices and bad choices in terms of lifestyle. Our expectation is that one’s genetic makeup might make one more inclined to be an arsonist or might make one more inclined to be a kleptomaniac. Do I think they can be changed? Yes.”

And in 2009, on Michelangelo Signorile’s radio show, Blackwell reaffirmed his stance, saying, “People choose to be who they are, as they choose to break civil law and God’s law. … I think you can choose not to be homosexual.”

At least five states and the District of Columbia have passed legislation forbidding mental health professionals from offering conversion therapy to minors.

In 1999, a report titled “Just the Facts About Sexual Orientation” was released specifically denouncing reparative therapy as having little or no effectiveness and instead contributing to discrimination. It was co-signed by 10 organizations: the American Academy of Pediatrics, the American Counseling Association, the American Association of School Administrators, the American Federation of Teachers, the American Psychological Association, the American School Health Association, Interfaith Alliance, the National Association of School Psychologists, the National Association of Social Workers and the National Education Association.

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