Everyone knows that breast is best. Not a day goes by without more evidence. "Breast-feeding for 20 months decreases risk of ovarian cancer by 50 percent." "Breast-feeding burns up to 500 extra calories a day." "Breast-feeding reduces infant mortality by 15 percent."

These are just three stories on Twitter in two days from from a sample of 1,000 Chinese women by Curtin University in Australia, a New York state health department campaign and the health education and literacy program in Pakistan.

But is breast-feeding far and away the best thing? Or have we done women a disservice by overstating its benefits?