Rwandan women attend a memorial service for genocide victims in April. After years of political turmoil, women in the country are narrowing the economic and political gap with men. Ben Curtis/AP hide caption

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Women stage a protest demanding equal pay for women at a 2012 rally in Miami. J Pat Carter/AP hide caption

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Ellen Pao, a former partner at Silicon Valley venture capital firm Kleiner Perkins Caufield & Byers, says women were excluded from all-male meetings at the company and denied seats on boards. The firm says she was fired for poor performance. Robert Galbraith/Reuters/Landov hide caption

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The human Y chromosome (left) holds the code for "maleness"; that's the X on the right. Andrew Syred/Science Source hide caption

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A long line for a men's room at a 2009 tech conference in Omaha, Neb. Photos of this situation have now inspired a Twitter feed. SleepyJeanne/Flickr hide caption

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