Brazilian mothers participate in a demonstration in 2011 for the right to breastfeed in public, in Sao Paulo, Brazil. Eduardo Anizelli/STF/LatinContent/Getty Images hide caption

itoggle caption Eduardo Anizelli/STF/LatinContent/Getty Images

Truvada can dramatically reduce the risk of HIV infection when taken as a preventative medicine — if taken every day. Studies are underway to determine if young people are likely to take the pill consistently. Justin Sullivan/Getty Images hide caption

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Kristen Caminiti cuddles her son Connor while doctors stitch her up following a C-section. Courtesy of Kristen DeBoy Caminiti hide caption

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Uzuri Pease-Greene, right, leads a walk through the public housing complex in the Potrero Hill neighborhood of San Francisco where her family lives. She is working to have the old buildings replaced. Talia Herman for NPR hide caption

itoggle caption Talia Herman for NPR

Most parents have a favorite child, psychologists say, even if they try to be fair. Hero Images Inc./Corbis hide caption

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People who practice free-range parenting say it makes kids more independent, but others see it as neglect. State and local laws don't specify what children are allowed to do on their own. iStockphoto hide caption

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A health worker with Doctors Without Borders carries a child suspected of having Ebola at the treatment center in Paynesville, Liberia, last October. Ebola is especially deadly for young children and babies. About 4 in 5 infected died. John Moore/Getty Images hide caption

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The ParaGuard IUD, which releases copper into the uterine cavity, can last up to 10 years. In clinical studies, the pregnancy rate among women using the device was less than 1 pregnancy per 100 women annually. Mark Harmel/Science Source hide caption

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Mary Harris was relieved when Stella was born with a mop of thick black hair, as if she had been protected from the chemo somehow. Courtesy of Howard Harris hide caption

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The number of children who need glasses has risen quickly across East Asia and Southeast Asia. But some parents and doctors in China are skeptical of lenses. They think glasses weaken children's vision. Imaginechina/Corbis hide caption

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Chef David Iott explains the perfect way to prepare risotto to Stanford students. Courtesy of Stanford's Residential and Dining Enterprises hide caption

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Emily Neblett, a patient at the Monroe Carell Jr. Children's Hospital in Nashville, Tenn., demonstrates circuit pieces from the mobile maker space that are connected by magnets. Noah Nelson/Youth Radio hide caption

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Research into how the human brain develops helps explain why teens have trouble controlling impulses. Leigh Wells/Ikon Images/Corbis hide caption

itoggle caption Leigh Wells/Ikon Images/Corbis