Women who breast-feed their babies for at least six months are more likely to achieve a healthy weight after pregnancy, Ostbye adds.

CNN: STORY HIGHLIGHTS

About 70 percent of Caucasian women like Bradley now breast-feed their babies.

NPR: Study: Breast-Feeding Decreases Cancer Risk

And if we're going to remove formula samples for women to promote breast-feeding, we better come up with a plan to feed the babies of that 5% of women who can't sustain them -- with 4 million births a year, that's 200, 000 moms who need extra help.

CNN: Is the medical community failing breast-feeding moms?

On the one hand, she argues that nearly the only biological difference between men and women is that men can't breast-feed.

WSJ: Do as I Do, Not as I Say

Lieberman says that the findings may have been affected by the attitude of the women themselves, who said they wanted to exclusively breast-feed but were also open to using formula.

CNN: How formula could increase breast-feeding rates

At the Brigham and Women's Hospital, Susan Bradley has decided to breast-feed Michaela Rose, born Tuesday morning.

NPR: Study: Breast-Feeding Decreases Cancer Risk