The District of Columbia Council on Tuesday unanimously approved a bill that prohibits therapies that attempt to alter the sexuality or gender identity of LGBT youth.

Mayor Vincent Gray is expected to sign the legislation.

When the bill is signed into law, Washington D.C. will become 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.”

Sarah Warbelow, legal director for the Human Rights Campaign (HRC), the nation's largest LGBT rights advocate, praised the move.

“While the LGBT youth in our nation's capital will soon be protected once this bill is signed into law,” Warbelow said in a statement, “HRC is committed to making sure these kinds of protections are secured throughout the entire nation.”

Groups opposed to gay rights have lost legal challenges to similar laws in California and New Jersey.