The judges added that allowing same-sex marriage could increase incidence of HIV-Aids in India and expressed concern that it could "negatively affect the psychological and emotional development of children raised by same-sex couples".
But last weekend, the petitioners received a major boost when Indian Psychiatric Society (IPS) - the country's leading mental health group which represents more than 7,000 psychiatrists - issued a statement in their support.
"Homosexuality is not a disease," the IPS said in a statement, adding that discrimination against LGBTQ+ people could "lead to mental health issues in them".