Up till now, all babies have had two genetic parents. That could soon change. Klöpper & Eisenschmidt GbR/iStockphoto hide caption

itoggle caption Klöpper & Eisenschmidt GbR/iStockphoto

Michelle Obama eats lunch with school children at Parklawn Elementary School in Alexandria, Va., in 2012. The first lady unveiled new guidelines Tuesday aimed at cracking down on the marketing of junk food to kids during the school day. Saul Loeb/AFP/Getty Images hide caption

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Sophia Jarvis, 4, of Berkeley, Calif., is one of the few children diagnosed with the polio-like disease, which left her arm paralyzed. She attended a press conference Monday at Stanford University with her dad, Jeff. Martha Mendoza/AP hide caption

itoggle caption Martha Mendoza/AP

Joscelyn Benninghoff, 10, goes over the results of her cholesterol test with her mother Elizabeth Duruz (right) and Dr. Elaine Urbina at Cincinnati Children's Hospital in 2011. Al Behrman/AP hide caption

itoggle caption Al Behrman/AP

In the Institute for the Unsalvageable in Sighetu Marmatiei, Romania, shown here in 1992, children were left in cribs for days on end. Tom Szalay hide caption

itoggle caption Tom Szalay