Lant Pritchett

Most experts agree the shift to fewer kids is being driven by good things, including education and economic gains for women and plummeting teen pregnancy rates.

But there are also challenges.

Economists say families in all the countries that drive global GDP, from China to Germany to the U.S.,

are now having too few children to maintain a stable population and robust workforce.

Lant Pritchett is at the London School of Economics.

Many experts say the trend toward fewer children in the U.S.

and around the world will continue, a pattern that's already straining pension and health care systems in some countries as populations age and shrink.

Brian Mann, NPR News.

It's hard to maintain the dynamism of the economy.

You can't get people to do all kinds of work, from electricians to plumbers to everything else.

It's hard to maintain the dynamism of the economy.

You can't get people to do all kinds of work, from electricians to plumbers to everything else.