DC Mayor Vincent Gray on Monday signed a bill that prohibits therapies that attempt to alter the sexuality or gender identity of LGBT youth.

“I am proud to sign a bill that protects youth & their families from the discredited practice of conversion therapy,” Gray said in tweeting a photo of himself signing the bill into law.

Washington, DC becomes the third jurisdiction behind California and New Jersey to outlaw such therapies.

The legislation bans “efforts [by licensed mental health providers] to change behaviors, gender identity or expression, or to reduce or eliminate sexual or romantic attractions or feelings toward a person of the same sex or gender.”

LGBT advocate the National Center for Lesbian Rights (NCLR) earlier this year launched its #BornPerfect campaign, which aims to raise awareness about “the serious harms caused by attempts to change a young person's sexual orientation or gender identity.”

“This law ensures that mental health practitioners can no longer abuse their power to harm young people and families by propagating the dangerous lie that there is something wrong with being LGBT or that therapy can change their core sexual orientation or gender identity,” NCLR Staff Attorney and #BornPerfect Campaign Coordinator Samantha Ames said in a statement. “By signing this bill into law, Mayor Gray has taken an important step to protect the health and safety of LGBT youth and to prevent unscrupulous therapists from preying on vulnerable families.”