(CNN) —  

Oregon this week became the third state to ban conversion therapy, a widely discredited practice aimed at changing the sexual orientation of individuals who identify as gay or lesbian.

Democratic Gov. Kate Brown, the first openly bisexual governor in the country, signed on Monday the bill into law, which bars therapists from performing conversion therapy on individuals under 18. Similar laws already exist in California, New Jersey and Washington, D.C.

RELATED: White House seeks ban on gay and gender identity conversion therapies

The American Psychological Association has repudiated the practice of gay conversion therapy, citing the negative effects on patients and the lack of evidence to suggest that the practice is effective.

The ban will not apply to religious groups and organization, only to mental health practitioners licensed by the state.

President Barack Obama also called for a national ban on the practice last month, but religious groups and conservatives insist that such a ban would infringe on their religious freedom rights.

The White House released a statement last month in response to an online petition submitted to the White House calling for a ban on the practice.

“”The overwhelming scientific evidence demonstrates that conversion therapy, especially when it is practiced on young people, is neither medically nor ethically appropriate and can cause substantial harm,” Obama’s senior adviser Valerie Jarrett said in a statement. “As part of our dedication to protecting America’s youth, this administration supports efforts to ban the use of conversion therapy for minors.”