In the late 1960's, Paul Ehrlich warned that a Population Bomb was creating so many people they wouldn't be able to feed themselves within 20 years. The new book, What to Expect When No One's Expecting, is claiming the opposite: the root of America's problems is that the birthrate's declining. That means too few workers to care for the elderly, innovate and keep the economy growing. Is raising children just too expensive? Are liberated women working instead of staying home? What about abortion and contraception? Debate about population raises a host of hot-button issues, including immigration reform. If we're not producing enough people, why not import them?