Should the human race limit it's populations growth? Absolutely, I think any sensible being could understand the consequences of an earth unable to sustain its populace.   We must self regulate.   I think if someone calculated a number and posted it so we knew when it would be best to have children most would follow.  We are a more progressive society.  Half of marriages end in divorce.  We want to be single.  Those who want to have families and raise young ones, have at it.  Try and follow the numbers.  Most species having mating cycles, maybe we need to start going back to our roots.