Sure pre-marital sex is counter to catholic beliefs, but there's no reason why both things can't exist. If people are having sex because of a fear of aids instead of a fear of god then people are abstaining for the wrong reason.
One thing that confuses me is that the church does not advocate pre-marital sex because it can lead to unwanted pregnancies, but if people are going to have sex anyways then unwanted pregnancies are going to happen, for those who don't follow the Catholic religion. An ideal situation would be to have a child of your own volition and then raise him in somewhat of a stable situation -- this is just as much a service to god, if not moreso, than simply waiting for marriage to have sex in the first place.
Certainly in an 'ideal' world, everyone would wait till marriage to have sex, but people are people and not following a chosen world view is no reason to die.
The hypocrisy and delusional thinking of the Catholic church never fails to astound me.