The Terrence Higgins Trust has launched a new website to help GPs better understand the health needs of gay men.
The move comes as research shows almost 44% of homosexual males have not disclosed their sexuality to their doctor.
This reluctance is being blamed on poor communication about sex and sexuality with staff in GPs' surgeries, and may mean some people are not getting the support they need.
This could result in unequal access to quality care for gay and bisexual men, as they may feel unable to share important lifestyle and sexual health information with GPs.
The website hopes to change this, and also provides advice on what GPs should ask gay patients in a bid to foster a more caring environment in practices.
The site also has advice for patients, and explains the benefits of discussing their sexuality with a GP to improve the level of care they receive.
Marc Thompson, programme development manager at the Terrence Higgins Trust, said "It's not always easy coming out to your GP, but it may be one of most important things you can do to keep yourself healthy.
"If your doctor knows about your sexuality, you can openly discuss your life, relationships and health concerns.
"They can also keep an eye out for any health problems relevant to you and your lifestyle."