Ben Carson attends the National Action Network (NAN) national convention at the Sheraton New York Times Square Hotel on April 8, 2015, in New York City.
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Carson speaks during the 41st annual Conservative Political Action Conference (CPAC) at the Gaylord International Hotel and Conference Center on March 8, 2014, in National Harbor, Maryland.
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Carson speaks to guests at the Iowa Freedom Summit on January 24, 2015, in Des Moines, Iowa.
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Carson is surrounded by supporters as he waits to be interviewed at the annual Conservative Political Action Conference (CPAC) at National Harbor, Maryland, outside Washington on February 26, 2015.
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Carson speaks at the South Carolina Tea Party Coalition convention on January 18, 2015, in Myrtle Beach, South Carolina. A variety of conservative presidential hopefuls spoke at the gathering on the second day of a three-day event.
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Carson delivers the keynote address at the Wake Up America gala event on September 5, 2014, in Scottsdale, Arizona.
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Carson speaks during the 41st annual Conservative Political Action Conference (CPAC) at the Gaylord International Hotel and Conference Center on March 8, 2014, in National Harbor, Maryland.
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Carson speaks during the National Prayer Breakfast at the Washington Hilton on February 7, 2013, in Washington.
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Honoree and director of pediatric neurosurgery at Johns Hopkins University, Carson poses with actor James Pickens Jr. at the Jackie Robinson Foundation Annual Awards Dinner on March 16, 2009, in New York City.
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Before his jump into conservative politics, Carson was known for his work as a neurosurgeon. Carson was awarded the Presidential Medal of Freedom by then-President George W. Bush on June 19, 2008. At that time, he was the director of pediatric surgery at Johns Hopkins Hospital in Baltimore, Maryland.
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In a story that garnered international attention, Carson was ready to separate a pair of 10-year-old Indian girls, Saba and Farah Shakeel, who are joined at the head in New Delhi, India. Here, he addresses a press conference at the Indraprashtra Apollo Hospital on October 4, 2005.
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Carson and a team of 20 specialists approved the procedure after studying the girls' brains; however, their parents were worried about their daughters' lives and did not give doctors permission to operate. The surgery did not happen.
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Carson observes the start of neurosurgery proceedings at the Raffles Hospital in Singapore on July 6, 2003. Carson and Dr. Keith Goh, left, performed a complex operation that was unsuccessful to separate 29-year-old twins Ladan And Laleh Bijani, who were joined at the head.