Everyone who has had children has asked themselves the question. The answers leave one feeling a bit squeamish, because the answers are all tautologies. The simplest is some version of: Because people have children. The more complicated responses – to make little caretakers for ourselves, for example – beg the question off to another, underlying tautology (We want to live because we live, in this case). There is no immediately obvious rationale.
The question in question is just the sort of question which religion purports to answer. But answers from divine purpose fare no better than circumstantial answers. The simplest answer from religion is: Because God commands it, which does not differ functionally from the first statement above, ‘Because people have children’. More nuanced responses again beg off to deeper tautologies, like the famed divine mission statement from the Christians: Man’s chief end is to glorify God and enjoy Him forever. The statement is lovely, but it is devoid of functional content. After thorough contemplation, we are still left standing around, awaiting the Lord’s instructions before we can get on with the glorifying and enjoying.
These tautologies lurk at the bottom of all teleology. No attempts to divine purpose from conditions avoid the fate of Leibniz’s theodicy. When applied, teleological excursions all discover the type of gem unearthed by Dr. Pangloss. Study of a language’s syntax alone, will never reveal the language’s semantics. What is cannot tell us why it is, any more than it can tell us what ought to be. Attempts to divine purpose from structure, while operating strictly within the structure, are futile.
So, why have children? Why not? Or more precisely, why ask why? It is not a fit question.