There is one benefit that does have a larger and more robust evidence base: the link between breastfeeding and cancers, in particular breast cancer. Across a wide variety of studies and locations, there seems to be a relationship here, and a sizable one—perhaps a 20 to 30 percent reduction in the risk of breast cancer. Breast cancer is a common cancer—almost 1 in 8 women will have a form of it at some point in their lives—so this reduction is big in absolute terms.
