I tot it was more of a how much lower can you sink sort of
thing. Or rather cost benefit analysis.
If you're well-off, having children will be a burden to you and
won't really make your life better materially.
If you're poor, then having more children means more hope for
your future if they turn out to be genuises. and you can't get much
poorer anyway.............
there's been plenty of psycho-metric and sociological studies
linking cognitive ability, social economic circumstances and things
like the number of children and unplanned/out of wedlock
pregnancies .....
but it's not something politically corrent to put out in a forum
bah ....