I don't think not having a kid is, itself, controversial. I think that telling others who want children not to have them is the controversial bit. On the one h

I don't think not having a kid is, itself, controversial. I think that telling others who want children not to have them is the controversial bit. On the one hand, it is a very effective way to reduce your carbon footprint if you can do it. On the other hand, for many people it conflicts with one of the most basic human desires, which is life-defining for lots of the population. As an analogy, if you asked people to be celibate you could guarantee that no new babies would come along even if birth-control-methods failed; a huge net positive! Despite that, sex is a basic human experience that many see as integral to their vision of a life, and it'd be controversial to seemingly impose that restriction on others. tl;dr: no controversy in you doing you, sometimes controversy in you asking others to similarly do you