A doctor in California has diagnosed a gay man with chronic “homosexual behaviour” after a routine medical examination, which she later defended was still medically classified as a “disease”.

Earlier this year, Matthew Moore said he started seeing the new doctor who suggested he undergo a complete physical examination.

The tests revealed that he was B-12 deficient, and had high blood pressure and high cholesterol — conditions that Mr Moore joked were “normal for me”.

When Mr Moore, who is openly gay, went back to the Manhattan Beach office to discuss these findings, the nurse gave him the results of his physical.

Among other diagnoses, the doctor listed “homosexual behavior (302.0)”.

“Homosexual behavior” was also listed as a “chronic condition” on Mr Moore’s patient plan.

He said: “My jaw was on the floor.

“At first, I kind of laughed, I thought, ‘Here’s another way that gay people are lessened and made to feel less-than,’ and then as I thought about it and as I dealt with it, it angered me.

“When I look up code 302.0 and its sexual deviancy or mental illness, and that code has been removed or suggested heavily not to be used since 1973”.

At the suggestion of an attorney, he later returned to the office to let the doctor explain her decision.

Asked about how a person could be treated for homosexual behavior, the doctor said that it was “still up to debate” and that being gay is “still being thought of as a disease”.

“I was dumbfounded”, Mr Moore said.

He said he does not take issue with his sexual orientation noted on his medical chart, but he does have a problem with it listed under chronic conditions.

He added: “Government tells us, often times, that we’re not equal.

“Many churches tell us that we’re sinners, and now here’s a medical professional telling us that we are sick. And it’s got to stop”.

Unsatisfied with his doctor’s response, Mr Moore wrote a letter to the Torrance Memorial Physician Network and received a note of apology in return.

He also received his $30 (£19.30) co-pay insurance fee back.

Heidi Assigal, senior director of Torrance Health Association, Inc., wrote: “We fully appreciate your frustration and anger related to your experience and are committed to ensuring that such events are not repeated.

“We would like to unequivocally state that the Torrance Memorial Physician Network does not view homosexuality as a disease or a chronic condition and we do not endorse or approve of the use of Code 302.0 as a diagnosis for homosexuality.”

Mr Moore said he does not plan to file a lawsuit against the doctor, who he asked remain anonymous to protect her reputation.

He said he was inspired to tell his story to let others know that if something like this happens, “you have to speak up.”

He added: “If I was a 14-year-old in a small town in Indiana, where I’m from, and I had a doctor tell me or my parents that I was sick because they thought I was gay, it would’ve been very damaging”.

Earlier this month, a San Diego County clerk who had moved against the resumption of the issue of same-sex marriage licences in California, withdrew a legal bid to stop them from taking place.

Ex-Chelsea footballer Mateja Kežman also recently came under controversy for saying that homosexuality is “a disease that should not be promoted”.