Friday is International Day Against Homophobia and Transphobia. To mark the day NAT is repeating its call to legalise gay marriage as an important step to challenging the homophobia which fuels the UK's HIV epidemic.
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. If you don't believe you are worth anything, why would you value yourself?
This devaluing of yourself and your health can result in behaviour such as high risk sexual activity or injecting drugs  which are currently fueling the HIV epidemic amongst gay and bi-sexual men.
Around seven gay or bisexual men a day in the UK are getting HIV and it remains one of the most serious infectious diseases we face. About 100,000 people are living with HIV in the UK - including approximately one in twenty gay and bisexual men.
Recent research by Stonewall  and others, including the Department of Health  show that lesbian and gay men have higher levels of substance abuse and mental health concerns, due in considerable part to ongoing stigma and discrimination.
Recent evidence also suggests combating institutional discrimination through opening civil marriage to gay and lesbian people can significantly influence their patterns of health. 
NAT believes, 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.