Amazon has removed English-language books by a man largely considered "the father of conversion therapy" from its site following mounting pressure from LGBTQ activists.

Dr. Joseph Nicolosi, founder of the now-shuttered Thomas Aquinas Psychological Clinic, as well as the National Association for Research and Therapy of Homosexuality (NARTH), authored several how-to guides directed to parents of LGBTQ youth, including "A Parent's Guide to Preventing Homosexuality." His books are some of the most well-known works about conversion therapy, the pseudoscientific practice of trying to change a person's sexual orientation or gender identity.

"I would say many survivors of conversion therapy could trace their trauma to Nicolosi," Sam Brinton, head of advocacy and government affairs at The Trevor Project and a survivor of conversion therapy, told NBC News. "His work lent credibility under the guise of 'science' to conversion therapy, even though the practice has been disputed and discredited as dangerous and harmful by medical experts."