As part of International Day Against Homophobia and Transphobia, the National AIDS Trust is repeating its call to legalise equal marriage “as an important step to challenging the homophobia which fuels the UK’s HIV epidemic”.

The National AIDS Trust (NAT) said in a statement: “Many gay men and women still continue to suffer discrimination and prejudice in their lives. Banning same-sex couples from marriage endorses this discrimination and sends out a clear message that same-sex relationships aren’t equal to opposite sex couples.

“This discrimination leads to low self esteem and internalised stigma amongst many gay men. Low self esteem is proven to have an impact on the way people look after themselves and make decisions about their health and wellbeing.”

Recent research by Stonewall shows that lesbian and gay men have higher levels of substance abuse and mental health concerns, due in considerable part to ongoing stigma and discrimination.

Gay, bisexual, and other men who have sex with men (MSM) continue to be disproportionately affected by the spread of HIV; accounting for almost half of all new cases in 2011.

NAT added: “Same-sex marriage is a key step towards ending stigma and discrimination towards gay people by encouraging current and future generations to treat everyone equally, no matter what their sexual orientation.

“The passing of this legislation by the House of Lords will be a milestone in celebrating gay people, gay communities and gay sexuality. It also crucially helps to promote social, physical and mental health for all people in the UK and would help reduce the rising number of new HIV diagnoses amongst gay men.”