Campaigners in India challenging the country's decriminalization of gay sex are being asked to define what is 'unnatural' intercourse.
An old colonial law which outlawed same-sex relationships and made them punishable by a 10-year jail term, was overturned by the Delhi High Court in 2009.
However, gay sex is still frowned upon by many Indians and political, social and religious groups want to reinstate the 148-year-old law.
Section 377 of the colonial Indian Penal Code defined homosexual acts as 'carnal intercourse against the order of nature'.
The debate returned to the Indian Supreme Court on Wednesday and judges are asking anti-gay campaigners to clarify what 'unnatural sex' is.
'The meaning of the word has never been constant,' Justices GS Singhvi and SJ Mukhopadhyaya asked a petitioner who challenged the judgement, the BBC reported.
They added: 'We have travelled a distance of 60 years. Now it is test-tube babies, surrogate mothers. They are called discoveries. Is it in the order of nature? Is there carnal intercourse?'
The decriminalization of gay sex was a landmark judgement and was hailed by human rights campaigners.