SINGAPORE - The law criminalising gay sex has been in the spotlight in recent weeks, amid talk of a possible review. The Straits Times looks at some of the key issues.

What is Section 377A about?

Section 377A of the Penal Code is a law criminalising sex between men, which is not enforced.

It was introduced in 1938 by the British colonial government, and was likely partially aimed at stopping European men from engaging Asian male prostitutes, based on documents declassified by the UK government between 2014 and 2016. Before Section 377A was introduced, the colonial government used a different, more loosely worded law - Section 377 - to prosecute men who had sex with men.

This law was adopted from the Indian penal code in 1872 and criminalised "carnal intercourse against the order of nature", which included oral and anal sex between heterosexual couples.

Similar laws were put in place in territories ruled by the British empire around the world, including India and New Zealand. Some of these countries have since repealed such laws over the years.

Singapore kept Sections 377 and 377A after independence in 1965, but the Government repealed Section 377 in 2007 after a comprehensive review of the Penal Code. A new law was instituted in its place, criminalising sex with a human corpse. Section 377A was retained - a decision which generated fierce debate in Parliament.

In a speech then, Prime Minister Lee Hsien Loong said the Government would not actively enforce Section 377A.

What was the outcome of recent legal challenges to Section 377A?

Since 2007, there have been several legal challenges contending that Section 377A should be struck down as it is unconstitutional. None was successful.

In 2010, a man was charged under Section 377A over having oral sex with another man in a public toilet cubicle. Although the Attorney-General's Chambers (AGC) later amended the charge against Mr Tan Eng Hong to one of committing an obscene act in public, he subsequently filed a suit challenging the constitutionality of Section 377A.

In 2012, gay couple Gary Lim and Kenneth Chee also challenged the law. The Court of Appeal eventually ruled in both cases that Section 377A was constitutional.

In 2019, three men filed another constitutional challenge against the law. They were: Dr Roy Tan Seng Kee, a retired general practitioner and an activist for lesbian, gay, bisexual and transgender (LGBT) rights; disc jockey Johnson Ong Ming; and Mr Bryan Choong, the former executive director of LGBT non-profit organisation Oogachaga.

The Court of Appeal, led by Chief Justice Sundaresh Menon, ruled that the law would stay but was "unenforceable in its entirety".

In its arguments for the case, the AGC said the question of whether to repeal Section 377A is a deeply divisive socio-political issue that should be decided by Parliament, not the judiciary.

Why have Articles 9 and 12 of the Constitution been cited in legal challenges to 377A?

Many of the constitutional challenges to Section 377A have revolved around these two articles of Singapore's Constitution.

Article 9 states: "No person shall be deprived of his life or personal liberty save in accordance with law."

Article 12 states: "All persons are equal before the law and entitled to the equal protection of the law."

Constitutional challenges to Section 377A have contended that the law is not consistent with these articles, and hence should be void.

In their legal challenge, Mr Lim and Mr Chee argued that the right to life and personal liberty under Article 9 should include a right to privacy and personal autonomy for a person to express love towards another human being.

But the apex court rejected this interpretation, holding that the phrase "life or personal liberty" refers only to a person's freedom from an unlawful deprivation of life and unlawful incarceration.

Lawyer M. Ravi, acting for Mr Tan Eng Hong, had argued that Section 377A was absurd because it criminalised a minority based on a core aspect of their identity that was unchangeable.

The court rejected this, saying there were still conflicting scientific views on whether sexual orientation is unchangeable, and it was thus premature to express any conclusive views on it.

The court also said Article 12 does not cover the issues involved in Section 377A. While the provision specifically prohibits discrimination based on religion, race, descent or place of birth, the words "gender", "sex" and "sexual orientation" are noticeably absent.

In throwing out the challenge against Section 377A in February this year, the Court of Appeal noted that the courts had established another approach to the "reasonable classification" test used to determine if a law is legal under Article 12.

This could make a difference to how Section 377A is evaluated, depending on how the legislative object of Section 377A is framed.

If Section 377A is a law meant to express societal disapproval of homosexual acts between men, then it would not violate the "reasonable classification test" and will be considered constitutional under Article 12.

But if the object of Section 377A is to show societal disapproval of homosexual conduct in general, or to safeguard public morality generally, then that would strengthen the case that Section 377A falls foul of the "reasonable classification" test.

That is because in these scenarios, Section 377A would appear to be under-inclusive because it does not criminalise female-female homosexual conduct, for instance.

Similarly, if Section 377A is a law meant to express societal disapproval of male prostitution, it may then be considered over-inclusive, and thus also unconstitutional under Article 12.

When was 377A last debated at length in Parliament?

In October 2007, as the House debated amendments to the Penal Code, then Nominated MP Siew Kum Hong filed a citizen's petition to repeal Section 377A. The move sparked a passionate debate on the topic with fierce arguments from both sides.

Mr Siew, a lawyer, appealed for gay men to have equal treatment under the law, arguing that criminalising sex between men discriminates against them and is unconstitutional.

Then Nominated MP Thio Li-Ann, a law academic, called for the retention of the law, saying repealing it would "further batter the institution of marriage".

Most People's Action Party MPs argued for keeping the law on the books to signal society's disapproval of the homosexual lifestyle, but not enforcing it so as not to actively oppress gays.

Former Punggol East MP Charles Chong was among the few who spoke out in favour of repeal. He said that if homosexuality is inborn, it would be wrong to criminalise and persecute those who are born different, regardless of how conservative Singapore society claims to be.

Workers' Party chairman Sylvia Lim said her party would not be calling for the law to be abolished as it had not come to a consensus on the matter.

Wrapping up the debate then, PM Lee said the Government's position was that it was better to accept the legal untidiness and ambiguity of keeping the law on the books, while not proactively enforcing it to "maintain a balance, to uphold a stable society with traditional heterosexual family values, but with space for homosexuals to live their lives and to contribute to the society".

How has the public debate evolved since then?

In 2018, veteran diplomat Tommy Koh called on the gay community in Singapore to mount another challenge to the law, after India's Supreme Court struck down the country's law against consensual gay sex.

Former attorneys-general Walter Woon and V.K. Rajah also separately said it was not desirable for the Government and Parliament to direct the AGC not to prosecute offences under Section 377A.

In a paper published in 2019, former chief justice Chan Sek Keong called for a review of Section 377A.

In it, he asked whether the law violates the fundamental rights of all to equality before the law and equal protection under the law, as provided for under Article 12 of the Constitution.

What did the Attorney-General say in response to these calls?

Following the comments by Mr Woon and Mr Rajah, Attorney-General Lucien Wong said in 2018 that the Public Prosecutor retains independence in deciding whether to pursue a case under Section 377A.

The police, when conducting investigations into an offence under the law, "will decide whether or not there is sufficient basis to refer the case to the Public Prosecutor".

The Public Prosecutor will then determine whether to charge an offender under the law, and in doing so exercises his independent discretion solely on the basis of his assessment of the facts, the law and the public interest.

"While the PP (Public Prosecutor) is entitled to consider public policies in exercising his discretion, these do not fetter the exercise of prosecutorial discretion," he had said.

"The Public Prosecutor's exercise of prosecutorial discretion has always been, and remains, unfettered. In the case of Section 377A, where the conduct in question was between two consenting adults in a private place, the Public Prosecutor had, absent other factors, taken the position that prosecution would not be in the public interest. This remains the position today."

How did the apex court rule on the most recent challenge?

In February, the Court of Appeal, led by the Chief Justice, held that Section 377A is completely unenforceable in its entirety, meaning that while the law will stay on the books, it cannot be used to prosecute men for having sex with other men.

Legal scholars and the gay community lauded the decision for giving gay men real protection from prosecution under the law.

The apex court said that the Attorney-General's comments in 2018, when he said the Public Prosecutor would not prosecute two consenting men for having sex in private, had given legal significance to the political compromise struck in 2007 when PM Lee said the law would not be proactively enforced.

Mr Wong's representations had also given people a legitimate expectation of not being prosecuted under Section 377A, based on the administrative law doctrine of substantive legitimate expectations, the court said.

As such, Section 377A would remain unenforceable unless and until the Attorney-General of the day revokes the 2018 representations.

Given this, the three men who challenged the law - Dr Tan, Mr Ong and Mr Choong - do not currently face any real and credible threat of prosecution.

They thus do not have the legal standing to mount constitutional challenges against the law, the court said, dismissing their bid.

The ruling could also mean that other gay men will not have the standing to challenge the constitutionality of Section 377A, unless and until the Attorney-General's stance changes.

How did the Government respond to the latest court ruling?

Following the Court of Appeal's ruling in February on Section 377A, Home Affairs and Law Minister K. Shanmugam said the Government is carefully considering the best way forward on the law.

He also reiterated the Government's stance on the law, noting PM Lee had said in 2007 that Singaporeans want "a stable society with traditional heterosexual family values, but with space for homosexuals to live their lives and to contribute to society".

But Mr Shanmugam, who made the remarks in Parliament when responding to questions from MPs on the ruling, had also said that public policies need to evolve to keep abreast of changes in views in society, and legislation will also have to evolve to support updated policies.

He said that if the Government decides to move on the law, it will "do so in a way that continues to balance these different viewpoints, and avoids causing a sudden, destabilising change in social norms and public expectations".

Shortly after, the Government started its review of the law, consulting widely, including religious and LGBT groups.