Sexually transmitted infections and hiv==risk of catching any of them per partner if sex only once with him?

Always a risk. Percentages have no meaning when it comes to an individual patient. You should be tested extensively, but more importantly, protect yourself and trust nobody when they profess to not having stds.

Related Questions

Where in the world is the most likely place to get sexually transmitted infections and HIV?

Anywhere. The most common would be in countries in which sexual promiscuity is rampant and where HIV often goes untreated so that viral loads are quite high.
Several areas. Africa is endemic, but South Florida (Palm Beach and south) has the United States highest concentration of HIV infected individuals.
STD spares no area. Anywhere in the world is a potential place for STD with unsafe sex. The appearance or hygienic habit of a partner does not provide prediction. Obviously sex workers would be the most likely transmitter. Usually the poorer the area, the less selective are the sex workers, the more likely you are going to contract STD (Africa, SE Asia etc)

Can birth control pills protect me from sexually transmitted infections (stis), including hiv/aids?

No. Birth control pills may protect you from pelvic inflammatory disease but will not protect you from hiv.
No. No, birth control pills do not protect you from sexually transmitted infections or hiv/aids. They just protect you from pregnancy. The only way to protect yourself from sexually transmitted infections, including hiv/aids, is through the use of barrier protection (condoms or dental dams).

Will birth control pills protect me from sexually transmitted infections (stis), includin hiv/aids?

No. Birth control pills protect against pregnancy if taken promptly every day. You need barrier protection like condoms in addition to birth control pills to prevent sexually transmitted infections.
STDs. Birth control pills will not protect you from anything, including pregnancy (although it makes pregnancy infinitely less likely). Condoms will provide reasonable protection from most stds, but even these can fail because of leakage or breakage. Be careful out there.

Do birth control pills offer any protection from sexually transmitted infections (stis), including hiv/aids?

No. No, they don't. You still need to use condoms even if you're taking birth control pills.
NO! Birth control pills offer zero protection from sexually transmitted infections and hiv/aids. If you are sexually active, make sure you use a condom every time to get the best protection against stis.

What laws are there for partner notification that has HIV or other sexually transmitted diseases?

Varies. State laws on this differ, and you would have to access your lawyer or the state legal system to learn what the rules are in your area.

Is sexually transmitted infections possible without having real sex?

Yes. Any exchange of bodily fluids can increase your risks of acquiring a sexually transmitted disease (i.e. Oral sex). Certain viruses out there are dna virues (herpes, hpv, etc.), which means once you have it, you have it for life; we can treat them...But we cannot cure them. If you've had an intimate encounter with a high-risk individual, play it safe and see your doctor so you don't lose sleep.

How do you talk to your partner about sexually transmitted infections prior to having sexual with them?

Openly and honestly. What a great question. There is not easy way to address the subject but it is so important. The decision to become sexually involved with someone involves trust. If you can not trust someone to have this conversation then it may not be time to be intimate. Protect yourself and your partner by being responsible and having an open dialogue about std testing.
Openly and honestly. If you are *thinking* about having sex with them, have that conversation, preferably NOT at the last moment. My usual rule is "If you can't talk about sex with someone, you shouldn't be having it with them! " And definitely use condoms- Remember that a negative test is only valid at that time (if that), so being "negative" isn't always accurate.