From the perspective of the species, it’s perfectly unmysterious why people have children. From the perspective of the individual, however, it’s more of a mystery than one might think. Most people assume that having children will make them happier. Yet a wide variety of academic research shows that parents are not happier than their childless peers, and in many cases are less so.
And I would pluck this quote from Mohler’s response:
Christians must see children as gifts from God, not as projects. We should see marriage and parenthood as a stewardship and privilege, not as a mere lifestyle choice.
I pretty much agree with Mohler here, so I’ll just point you there. Memory fades and dims, but my experience is that parenting has probably made me less happy as a percentage of my waking hours, but it has provided moments of happiness far greater than what I used to experience before we had kids.