Women with a family history of breast cancer can lower their risk by breastfeeding. Reporting in the August 10 issue of the Archives of Internal Medicine, researchers examined data from more than 60,000 women involved in the Nurses' Health Study II who reported in 1997 having had at least one pregnancy, and who provided detailed breastfeeding information. Women with a family history of breast cancer were 59% less likely to develop premenopausal breast cancer if they had ever breastfed, a risk reduction that's comparable to those among high-risk women taking tamoxifen to ward off cancer. The duration of lactation didn't affect risk, which was about the same among women who breastfed for three months or three years. Women without a family history of breast cancer did not benefit from breastfeeding. "These data suggest that women with a family history of breast cancer should be strongly encouraged to breastfeed," write the authors.