will still kill you. So the only recourse to safety for heavy smokers is to quit. The philosophy is simple: half the amount of poison is still poison. Particularly since the onset of cancer does not remain small for very long. It expands.
Now why won't people use the same philosophy and science elsewhere? Surely everyone can appreciate that a minor contraction of HIV virus is still enough to kill you? How about hepatitis? Same thing, right? So how come people still risk, and advocate to risk, the contraction of HIV and STDs using condoms that do not and cannot guarantee protection 100%? What, not willing to gamble on the 3-14% risk? You betcha.
So what about finding a better way to contain the risk? There already is. The QUIT SMOKING equivalent to STDs is called chastity. Sex only with your spouse. Assuming good health, and neither of you have been promiscuous, then you should be STD free. Of course, if one already has HIV, then QUIT means QUIT, doesn't it? Otherwise, where's the love in the loving act if it means a death sentence for the spouse?