A second federal lawsuit has been filed seeking to overturn California’s new ban on gay conversion therapy for those under the age of 18.

The Christian legal group Liberty Counsel filed a civil rights suit on Thursday in Sacramento naming as plaintiffs two southern California boys, aged 14 and 15, who have been undergoing so-called “reparative therapy” with psychologist Joseph Nicolosi.

According to the Associated Press, the suit claims the ban, scheduled to take effect on 1 Jan 2013, violates the teens’ freedom of speech and freedom of religion by denying them the chance to be cured of “unwanted same-sex attraction.”

The boys’ parents also are named as plaintiffs, along with Mr Nicolosi, two other southern California therapists, the National Association for Research and Therapy of Homosexuality, and the American Association of Christian Counsellors.

A similar lawsuit was filed on Monday by the Sacramento Pacific Legal Institute on behalf of psychiatrist, therapist and pastor, Dr Donald Welch, who operates one of San Diego’s oldest Christian counselling centres.

When the new law comes into force California will become the first place to outlaw the practice for people under the age of 18 in America.

Last weekend, Governor Jerry Brown said gay conversion therapy had “no basis in science or medicine”.

Britain’s largest professional body of psychotherapists has warned its members against attempting to “convert” gay people, after Christian therapist Lesley Pilkington finally had her membership of the BACP revoked on Wednesday.