DarthKermit: I can't see it ever being voluntarily introduced. China I think is the only country with a one child policy.
Perhaps in my life time (I'm nearly 45) I'll live to see natural population control because of collapses in the food chain we rely on, plus more and more wars and other conflicts over increasingly scarce resources that will also reduce population.
I have no children and have never wanted any. My only sister is 43 and has none either.
No it won't be voluntarily introduced - it will be imposed. No one volunteered to pay income tax (it was originally a temporary measure in the UK at least, introduced to fund wars) but we are all grudgingly accepting of that now.
First step will be a reversal of the present tax treatment.
One child - benefit paid
Second child - no benefit paid
Third child - 5% income tax penalty applied
Fourth child - 10% additional income tax penalty
or some such. Dressed up as a way of reducing government expenditure etc.

