Re: I don't get it...
Well, you all sorta have it right. First, HIV/AIDS is a virus that is spread thru sexual contact with an infected partner. Virgins, never having had sex, can't have HIV/AIDS (unless they contracted it thru a blood transfusion). So, with or without condoms, they cannot get it with eachother.
HIV (the virus that causes AIDS), is passed from an infected person to their partner during sex, because HIV lives in semen, which is ejaculated into the other partner. Gay sex is riskier because many gays have anal sex, when one partner inserts and thrusts his penis in the anus of the other until orgasm. During anal sex, because the tissues back there are very delicate, they bleed easier than vaginal tissues, so there's an easier entrance into the bloodstream, and therefore, the partner.
Although condoms are really a necessity for sexual activity in the Twenty First Century, it should be pointed out that they are only effective if they are used correctly and absolutely all the time, and that they are not at all effective if *gasp* they break, which can happen. You simply must know your partner.