42, U.S. Senator (D–NY). Kids: Theo, 5; Henry, 1

Talk about multitasking: Just five months after being tapped in January 2009 to replace Hillary Clinton as New york’s junior senator, Gillibrand became only the sixth woman in history to give birth as a sitting member of Congress. Considered a centrist Democrat, she has earned a reputation as a hardworking campaigner and fundraiser—two skills that should come in handy, as her first Senate campaign looms next November.