New Delhi, May 17: The Supreme Court today issued a notice to the Centre seeking its reply on a plea by a group of 20 former and current students of the prestigious IITs challenging section 377 of the IPC, which criminalises unnatural sex between two consenting adults of the same gender.

A bench of Chief Justice Dipak Misra and Justices A M Khanwilkar and D Y Chandrachud, while seeking a response from the government, ordered tagging of the plea with other similar petitions which have already been referred by the top court to a five-judge constitution bench on January 8.

The 20 IITians, including scientists, teachers, entrepreneurs and researchers of different age groups, who all are Lesbian, Gay, Bisexual and Transgenders (LGBT), have claimed that criminalisation of sexual orientation has resulted in a "sense of shame, loss of self-esteem and stigma".

Their plea was filed on behalf of LGBT alumni association of the IITs, which claims to have over 350 members. Among the petitioners, the youngest one is a 19-year-old student of IIT Delhi, while the oldest one graduated from an IIT in 1982.

The apex court had earlier referred to a constitution bench several pleas filed by eminent citizens and NGO 'Naaz Foundation' challenging the 2013 apex court verdict which had re-criminalised gay sex between consenting adults.

Section 377 of the IPC refers to 'unnatural offences' and says whoever voluntarily has carnal intercourse "against the order of nature" with any man, woman or animal, shall be punished with imprisonment for life, or with imprisonment of either description for a term which may extend to ten years, and shall also be liable to pay a fine.

"The petitioners contend that the continued existence of section 377 severely curtails the protection of equality, dignity, liberty and expression that the Constitution guarantees to all Indian citizen," the plea filed by the group of IITians said.

"The stigma, silence and violence that section 377 brings in its wake, deeply hurt the petitioners' professional promise and personal fulfilment," it said.

It has alleged that several petitioners have had to grapple with depression, self-harm and other mental health issues, all of which have had a very deleterious effect on their academic and career prospects.

The petition urged the court to intervene to finally settle the controversial issue as government and Parliament had been reluctant to examine it. On May 1, the top court had dealt with two separate pleas filed by LGBT rights activists Arif Jafar, Ashok Row Kavi and others including Mumbai-based NGO 'Humsafar Trust' which fights for LGBT rights.

The top court had on April 23 sought the Centre's reply on a hotelier's plea for striking down section 377. While agreeing to reconsider the 2013 verdict criminalising gay sex, the top court had in January said the section of people or individuals who exercise their choice should never "remain in a state of fear".

It had also said the determination of the order of nature was not a constant phenomenon as social morality changes from age to age.

The apex court is already seized of similar pleas filed by celebrities like dancer N S Johar, chef Ritu Dalmia and another hotelier Aman Nath challenging the validity of section 377 criminalising the consensual gay sex.

The Delhi High Court, on July 2, 2009, had legalised homosexual acts among consenting adults, holding that the 149-year-old law making it a criminal offence was violative of the fundamental rights.