The next generation of women need to strategize for a family. While writing Creating a Life, Sylvia Ann Hewlett found that a third of well-paid career women were childless at 40, and most hadn't planned it that way.

The "creeping non-choice" arises because most young career women believe they can wait until 40 to have kids. But statistics say a woman's fertility typically peaks by 30 and drops 50% by 35. By her early 40s, she has a 3% to 5% chance of having a baby, even using fertility techniques.

"If you want children, plan where you want to be at 45 and work backwards," says Hewlett. "Make time to find a partner. Seek out a company with policies that will help you have both work and family in your life."