Fifty years ago, the typical first-time mother in the U.S. took about four hours to give birth. These days, women labor about 6 1/2 hours. Carsten/Three Lions/Getty Images hide caption

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Environmental groups say a ban would protect consumers from the health effects of BPA that leaches from products including some soup cans. Chip Somodevilla/Getty Images hide caption

itoggle caption Chip Somodevilla/Getty Images

A package of K2, a concoction of dried herbs sprayed with chemicals sometimes called synthetic marijuana. New York moved to ban a wide range of products like these this week. Kelley McCall/AP hide caption

itoggle caption Kelley McCall/AP

This image shows the grid structure of the major pathways of the brain. It was created using a scanner that's part of the Human Connectome Project, a five-year effort which is studying and mapping the human brain. MGH-UCLA Human Connectome Project hide caption

itoggle caption MGH-UCLA Human Connectome Project

Aspirin helps reduce the risk of cardiovascular disease, but the jury's still out on cancer. iStockphoto.com hide caption

itoggle caption iStockphoto.com