InfraSuperman: "I do not understand why prostitution is illegal. Why should prostitution be illegal? Selling is legal. Fucking is legal. Why isn't selling fucking legal? You know, why should it be illegal to sell something that's perfectly legal to give away? I can't follow the logic on that at all. Of all the things you can do to a person, giving someone an orgasm is hardly the worst thing in the world. In the army they give you a medal for spraying napalm on people. Civilian life, you go to jail for giving someone an orgasm. Maybe I'm not supposed to understand it." - George Carlin
Technically, they are B-bombs (biological weapon), which you blow up in civil area.
So,... a closed-loop, ahem, "system", offers some reliable protection. =)
You are not missing much... maybe 20-80 contagious virii...
I think, its simply not under control. If something extremely profitable comes out of state control, they tend to ban it. Fallout 2 teaches you - what. =)