The Trump administration is weighing a series of measures to support families and reverse the US’s plunging birth rate. But if the country truly wants to confront its birth rate crisis, it must go beyond incentives and make family-friendliness a national priority. American cities are at the heart of that challenge. They are among the world’s most inhospitable places for families and children — and that must change. America’s birth rate has collapsed to near record-low levels, but that is not...