Objective: This study aimed to assess the trend of human fecundity over time in China.

So what might be the cause of these episodes of quite extraordinary downward shift in human fecundity?

Further, there are clear indications that even human fecundity is supposed to be promoted by the genial heat of the fires.

I maintain that a considerable degree of labour, and even privation, is a more efficient cause of an increased degree of human fecundity.