Psalm 127:4,5
As arrows are in the hand of a mighty man; so are children of the youth.
Happy is the man that hath his quiver full of them:
It's a question that bothers me greatly. When older people give an autobiographical anecdote, they often tell of coming from a family of 8 kids all raised in the same home. Often this comes from the mouths of very successful and accomplished individuals which dispels the myth about children's opportunities being jeopardized by competition with multiple other siblings.

The Duggar Family
But now it seems we want to have neatly manicured families with 2 but no more than 3 children. We are told to plan our families with a careful regard to time and resources. We buy into the concept that each child should have his or her own room so that the size of our family is limited to how expensive a house we can afford. It's even more disturbing to see this trend among Christians and Jews who have historically been known for raising huge families which is the most proven effective way to sustain the faith from one generation to the next. Now it seems we've stigmatized large families.
I'm sure there are a lot of theories out there as to why. But I blame Christians who have fallen away from opposition to birth control. It used to be that both Catholics and Protestants were united in the understanding that birth control is the wrongful frustration of the life creating purpose of sex in a marital context and that many social evils spawn from it. We act as if "oopsies" are to be avoided at all costs, but how many of us were "oopsies"? And how hypocritical is that to believe that no children are an accident but then act in such way as to prevent any accidental children? And how hypocritical is it for accidental children to do everything in their power to make sure they don't have accidental children of their own?
Or let's put this another way? Have we caused our "family planning" to supplant God's plan for our families?
Oh, and I'm about to be the father of a 4th child in January and this child was an "oopsie". As devout Catholics we don't use contraceptives ever. But this wonderful human being soon to be born may never have been possible if we did the planning instead of God.