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 discredited therapy.

Two years ago, in a radio interview with Tony Perkins, the president of the Family Research Council, which has been deemed a hate group by the Southern Poverty Law Center, Blackwell appeared to blame the deaths of six people 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.”

The American Psychiatric Association de-pathologized homosexuality in 1973, when it was removed from the Diagnostic and Statistical Manual of Mental Disorders. Other professional groups quickly followed suit:

In 1975, the American Psychological Association urged its members to help remove the stigma of illness from gay people.

In 1981, the World Health Organization removed homosexuality from its list of mental illnesses.

In 1994, the American Medical Association released a report calling for “nonjudgmental recognition of sexual orientation.”

And on June 26, 2015, in Obergefell v. Hodges, the U.S. Supreme Court decided in favor of same-sex marriage, writing that being gay is “a normal expression of human sexuality and immutable.”

Vice President-elect Mike Pence has also appeared to support conversion therapy. When he was running for Congress in 2000, Pence’s website declared that money set aside by the federal CARE Act, to help indigent HIV/AIDS patients, also be “directed toward those institutions which provide assistance to those seeking to change their sexual behavior.” (The Trump transition team has not responded for a request for comment.)

In 2011, freelance investigative journalist John Becker went undercover and secretly filmed a conversion therapy session at a Christian counseling clinic run by Marcus Bachmann, husband of former Minnesota representative Michele Bachmann.

Experts around the world have condemned conversion therapy as not only lacking empirical validity but as unhealthy, especially for young people, causing depression, anxiety, addiction and even suicide.

At least five states and the District of Columbia have passed legislation forbidding mental health professionals from offering conversion therapy to minors. Last year, a New Jersey judge ruled that a conversion therapy group called JONAH had violated the state’s consumer protection statute by fraudulently advertising a cure for being gay. The judge also found the group’s business practices “unconscionable.” As part of the settlement, in which JONAH was ordered to pay more than $3.5 million in legal fees and damages, the organization also was forced out of business and its therapists barred from practicing or even promoting conversion therapy in New Jersey.

Douglas Haldeman, a psychologist in Seattle, has written frequently on the topic. The term “reparative therapy” “inaccurately implies ‘broken-ness’ as the distinctive feature of homosexuality and bisexuality,” he wrote in the book “Homosexuality: Research Implications for Public Policy.” “The promotion of reparative or conversion therapy goes beyond its obvious market of disaffected lesbian, gay and bisexual people. This campaign attempts to influence public opinion and justify anti-gay discrimination by inaccurately portraying homosexuality as a mental disorder and a social evil. Conversion therapy, then, is more than just a clinical issue. It figures prominently in the national debate over lesbian and gay civil rights.”

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 against LGBT people. It was co-signed by 10 prestigious 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.