Happy Birthday: Cake, candles and cone-shaped hats make regular appearances at birthday parties. What gives? William Gottlieb/Corbis hide caption

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Opponents of same-sex marriage participate in the March for Marriage in Washington, D.C., on March 26, as the Supreme Court hears arguments on California's Proposition 8 ban on same-sex marriage. Nicholas Kamm/AFP/Getty Images hide caption

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One contemporary analysis links the increase in gender equality in a society with increased sexual empowerment of women and less sexual coercion. But there's more to it than that. iStockphoto.com hide caption

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Of Blocks And Books: Parents may be more likely to take a young daughter to the library than a son, and to read to the girl for longer periods of time, a new analysis suggests. Hulton Archive/iStockphoto.com hide caption

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Same-sex marriage advocates protest outside the county clerk's office in San Francisco on Feb. 14. Justin Sullivan/Getty Images hide caption

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