Lean in. Opt out. Have it all. None of the above.

A new audiobook based on a groundbreaking cross-generational study reveals both greater freedom and new constraints for men and women in their work and family lives.

Stew Friedman, founding director of The Wharton School's Work/Life Integration Project, studied two generations of Wharton college students as they graduated: Gen Xers in 1992 and Millennials in 2012. The cross-generational study produced a stark discovery - the rate of graduates who plan to have children has dropped by nearly half over the past 20 years. At the same time, men and women are now more aligned in their attitudes about dual-career relationships, and they are opting out of parenthood in equal proportions. But their reasons for doing so are quite different.

In his new book, Baby Bust: New Choices for Men and Women in Work and Family, Friedman draws on this unique research to explain why so many young people are not planning to become parents. He reveals good n