A senior government lawyer has said it “may not be proper” for the Delhi High Court to overturn a colonial-era law that bans “unnatural sex” in India.

Last month the High Court in Delhi finished hearing arguments in a suit brought by gay rights activists seeking to overturn Section 377.

Chief Justice AP Shah reserved judgement and asked both sides to submit transcripts of their arguments.

The government of India wants to retain Section 377. It was enacted in 1860 under the British Raj in line with the anti-sodomy laws in England at the time.

It punishes anyone who “voluntarily has carnal intercourse against the order of nature with any man, woman or animal” by imprisonment and criminalises a whole range of sexual acts from mutual masturbation, to fellatio and anal sex.

Additional solicitor general PP Malhotra’s 100-page written submission filed with High Court states:

“The court is not the authority to decide what should be the law or what should not be the law.

“These are the functions of the Parliament and the will of the Parliament is represented by its members. They know the will of their people, the difficulties of their people.

“It may not be proper for the court to assume the role and will of the people or to act as a Parliament to change the law.

“What are the laws and what could be the law should be left to the wisdom of the Parliament. Neither the Courts are equipped nor is it the function of the Court to decide what the law should be.

“The Courts have only to interpret the law as it is.”

In October Mr Malhotra told the High Court that homosexuality is a disease.

“Every citizen has the right to lead a decent and moral life in society and the right would be violated if such behaviour is legalised in the country,” he said.

“AIDS is already spreading in the country and if gay sex is legalised then people on the street would start indulging in such practices saying that the High Court has given approval for it.

“Legalising it would send a wrong message to our youth.”

“Show us one report which says that it is a disease,” Chief Justice Shah responded.

“A WHO (World Health Organisation) paper says that it is not a disease but you are describing it as a disease.

“It is an accepted fact that it is a main vehicle that causes (AIDS) disease but it is not a disease itself.”

In September the Chief Justice rejected government attempts to introduce religious texts as evidence.

“This is just one-sided version of a religious body which cannot be relied upon,” he said.

“This is part of religious doctrine. Show us some scientific report which says that gay sex should be criminalised.”

While the health ministry is fighting to repeal the law, on the grounds that decriminalisation will help stop the spread of HIV, the home ministry maintains that gay sex is the product of “a perverse mind.”

Health minister Anbumani Ramadoss called for the repeal of Section 377 in August at the 17th International Conference on AIDS in Mexico City.

The director of the United Nations Development Programme on HIV/AIDS has said that the fight against the disease in India will be helped if homosexual acts are decriminalised.

Jeffrey O’Malley told AFP that infections in the subcontinent, already an estimated 2.5 million, continue to rise.

“Until we acknowledge these behaviours and work with people involved with these behaviours, we are not going to halt and reverse the HIV epidemic,” he said.

“Countries which protect men who have sex with men … have double the rate of coverage of HIV prevention services, as much as 60%.”