What seemed like a burden can become a gift. iStockphoto hide caption

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Madison Fitzgerald, 20, holds her baby, Jake, in the neonatal intensive care unit at Texas Children's Hospital in Houston. Jake, who was born 16 weeks too early, receives donor breast milk every three hours by mouth. Carrie Feibel/KUHF hide caption

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Hormones clearly influence a women's health, but figuring out how is a tricky business. Andrew Ostrovsky/iStockphoto.com hide caption

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There's more than one reason to aim for a good night's sleep. Charles Taylor/iStockphoto.com hide caption

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Researchers stroked babies' faces with a paintbrush while they watched the same thing happening to a baby in a video. How long the babies in the experiment watched the screen gave clues to what they were thinking. Courtesy of Maria Laura Filippetti hide caption

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Disease susceptibility varies among ethnic groups, but medicine hasn't always recognized that. Jo Unruh/iStockphoto hide caption

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Six students and a visitor have fallen ill with meningitis at Princeton University in New Jersey, shown here in August 2013. All have recovered or are recovering, officials said. Bloomberg via Getty Images hide caption

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Estrogen affects cells in the eye's retina, which may help explain a possible link between glaucoma and estrogen levels. iStockphoto.com hide caption

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