While having a child is a deeply personal decision, it’s also shaped by culture, religion, economics and government policy. “No one has a good answer” as to why fertility varies among countries, says sociologist Andrew Cherlin of Johns Hopkins University. Eroding religious belief in Europe may partly explain lowered birth rates. In Japan, young women may be rebelling against their mothers’ isolated lives of child-rearing. General optimism and pessimism count. Hopefulness fueled America’s baby boom. After the Soviet Union’s collapse, says Cherlin, “anxiety for the future” depressed birth rates in Russia and Eastern Europe…

We need to avoid Western Europe’s mix of high taxes, low birth rates and feeble economic growth. Young Americans already face a bleak labor market that cannot instill confidence about having children. Piling on higher taxes won’t help. “If higher taxes make it more expensive to raise children,” says demographer Nicholas Eberstadt of the American Enterprise Institute, “people will think more about having another child.” That seems common sense, despite the multiple influences on becoming parents.