> It is possible for the human species to exist without cigarette smoke

Yeah, and it's possible for it to exist without whatever pleasures you enjoy too that I don't approve of. I'm sure I can invent some twisted, self serving reasoning to justify why your activity should be banned, as I don't like it, and my judgment is better than yours.

> It is not possible for the human species (or any form of mortal biological life) to exist without children.

No, but some people's kids we could do without. Especially the ones who want to ban everything.