I think most young family doctors would be pretty good. Medical training these days is very inclusive. I used to work at a clinic in Montreal that deals with a lot of this stuff (CLSC Metro), most of the doctors there are gay, and I learned a few things. So for what it's worth, here's the Ganja Rule Book on gay sex.
1. Always use condoms unless you're in a long-term relationship, you've both been tested, monogamous, yada, yada...
2. Condoms protect you against bugs that live in bodily fluids (HIV, Hep B), but they don't protect you from infection that may live in lesions in the periphery, eg. HPV virus in genital/anal warts (which may be outside of the condom covered geography), herpes simplex virus that may live around the mouth, or around the genitals (again, lesions may be outside of the area protected), and of course good old syphilis which is making a comeback. Syphilis ulcers may or may not be covered by condoms.
3. Many sexually transmitted illnesses are curable, usually bacterial infections (chlamydia, gonorhhoea, syphilis, trichomonas - a parasite, not a bacteria), most viral infections are not curable and you have them for life (HIV, HPV, Herpes, Hep B). If you're the kind of guy who has difficulty with commitments, beware before you commit to catching one of these livelong bugs.
4. Many people don't take HIV seriously any more. HIV is still not curable, although people are living longer with it.
5. Anal sex is riskier than vaginal sex because of the risk of microlacterations that could expose you to blood.
6. There is no such thing as safe sex, only safer sex. There is always a risk, one must try to minimize that risk.
