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.

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.)

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.