(Getty)

The US Supreme Court has upheld California’s ban on so-called gay conversion therapy.

An appeal to the Californian law, which bans any counselling that aims to change a child’s sexuality, was rejected today.

The most populous state in the US signed into law a prohibition on the use of so-called gay conversion therapy on anyone under 18 years of age in 2012.

And since the law was signed, making California the first state to do so, the state has had to combat multiple objections on religious grounds.

The latest was blocked today by the highest court in the land, as the Supreme Court rejected an appeal from three people, led by licensed therapist and minister Donald Welch.

California officials had previously urged the Supreme Court to not hear the appeal.

They had argued that the law doesn’t restrict what religious leaders can say, except in the case of state-licensed therapy sessions.

The law applies to licensed doctors, psychologists, family therapists and social workers, and subjects anyone who breaks it to discipline by state-run licensing bodies.

Licensed providers are however allowed to refer children to religious leaders.

Welch has been here before, having successfully secured a temporary exemption from the law in 2012, before it came into effect.

This was eventually overturned in 2013, and subsequent legal challenges were also turned away or not heard.

Psychologist Joseph Nicolosi, who died in March aged 70, also brought a lawsuit against California in 2012, which was rejected by the courts.

Nicolosi pioneered so-called gay cure therapy, and was co-founder of the National Association for Research & Therapy of Homosexuality.

He became a prominent proponent of the therapy, which has been widely debunked by experts, and a major figure in the ‘ex-gay’ movement.

Following New Mexico voting overwhelmingly to ban the practice, so-called gay conversion therapy is now prohibited in seven states.

As well as California and New Mexico, the harmful procedure has also been outlawed in New Jersey, Oregon, Illinois, New York and Vermont.