I'm reading Goldman's latest book, How Civilizations Die (And Why Islam Is Dying Too), and I highly recommend it. He writes:
The average cost of raising an American child to age 17 is $222,360, according to a 2010 survey by the U.S. Department of Agriculture. That's more than four years of after-tax income for the median American family, not counting university. Put it another way: a single child will cost nearly 30 percent of the median family's spending power over the first 17 years. Young families go into debt to raise children and pay the debts off when the children are grown. ...As I alluded to in a column in The Oklahoman ("Traditional Family Key to Economic Health"), I believe public policy should discourage this free riding. This is one of the reasons I plan to vote for Rick Santorum, who believes we should, as one scholar puts it, use "tax policy as pro-family, pro-natalism social policy."
Without other people's children, to be sure, the childless singles would starve in old age, because there would be no one to pay the taxes that fund their benefits. But nothing in the social safety net discourages free riding on other people's child rearing.