A Catholic hospital in California has refused to perform hysterectomy on a transgender man, saying in a statement that such a procedure would violate its religious beliefs.

Patient Evan Michael Minton, who was born a woman but has identified herself as male, said Mercy San Juan Medical Center in Carmichael cancelled a previously scheduled surgery on Monday.

"When I got that news, I fell on the ground and cried uncontrollably," said Minton, according to The Sacramento Bee "It hurt because of the fact that I'm being discriminated against based on my innate and immutable characteristics, and it also hurt because it put everything in flux."

The 35-year-old state legislative aide came out as transgender six years ago.

Minton and his surgeon, Dr. Lindsey Dawson, were surprised by the decision taken by the hospital, which is part of the Dignity Health chain.

"I was a little bit blindsided by it," said Dawson, a Sacramento obstetrician gynaecologist.

The hospital said the procedure was against its anti-sterilisation policy.

Dignity Health refused to discuss Minton's case, citing privacy laws.

"In general, it is our practice not to provide sterilisation services at Dignity Health's Catholic facilities," said spokeswoman Melissa Jue, adding that hysterectomies are only allowed to cure a "serious pathology and (if) a simpler treatment is not available."

Dawson said Minton needed the procedure.

"Gender dysphoria is very clearly a pathology. It's a recognised state of health," noting that national obstetrics groups recommend that transitioning transgender patients be put on hormones and provided with appropriate surgeries," said Dawson.

Minton had already undergone double mastectomy and is scheduled to have phalloplasty, or male organ reconstruction surgery, on Nov. 23.

The cancellation has depressed Minton.

"It makes me feel like I want to crawl out of my skin. It brings me to my knees, it gives me anxiety, it makes me so emotional and that's when I know that I need to take the next step in my transition. ... I want to live as the complete man that I know myself to be. That's all," he said.

Ben Hudson, executive director of Sacramento's Gender Health Center, explained that "we know that these are life-saving procedures for transgender individuals. It's not up to (hospitals) to decide."

Despite the cancellation, Dignity Health officials helped Dawson set up with emergency privileges at Methodist Hospital of Sacramento, which is not bound by Catholic doctrines.

"I don't blame the staff. I don't blame the administrators. I blame the (Catholic) doctrines," Dawson said.