A gay rights group seeks to intervene in a federal lawsuit challenging California's law which bans 'ex-gay' therapy to minors.

The first-in-the-nation law outlaws therapies that attempt to alter a minor's sexual orientation from gay to straight.

Two groups opposed to gay rights, the National Association for Research & Therapy of Homosexuality (NARTH) and Liberty Counsel, filed a federal lawsuit challenging the law and asking that the court block it from going into effect on January 1.

NARTH officials had testified against the measure and called on Governor Jerry Brown to veto the bill.

On its website, the group claimed that passage of the bill would “likely increase harms to minors through its unintended consequences.” Parents, the group explained, would be forced to seek out therapy for their children from “unlicensed, unregulated and unaccountable religious counselors.”

“The vast majority of anecdotal accounts of harm to children from SOCE [Sexual Orientation Change Efforts] seem attributable to these types of counselors and to religiously oriented programs.”

On Friday, the National Center for Lesbian Rights (NCLR) filed court papers seeking to intervene in the suit on behalf of Equality California (EQCA), a co-sponsor of the law.

“This lawsuit is a desperate attempt by extreme anti-LGBT groups to defend the indefensible – mental health professionals who subject young people to dangerous practices,” said NCLR Executive Director Kate Kendell in a statement. “The plain fact is that every mainstream medical and mental health association in the country has warned that these practices are ineffective and deadly. The state has the right and obligation to protect young people from this psychological abuse, which can lead to depression, substance abuse, self-harm, and even suicide.”

Since its passage, a New Jersey lawmaker has introduced legislation modeled after California's law.