 Bresch 's appointment as Chief Executive Officer was announced in 2001 and she officially took the position in January 2012 . Bresch was the first female CEO of a large pharmaceutical business . At the time , she was one of 18 female CEOs of a Fortune 500 company . She was ranked 31 in Fortune Magazine 's 2014 " 50 Most Powerful Women " list Bresch initially did not think her role as a female executive was significant . After seeing how few female candidates were available for positions that require a background in science and math , she became more interested in promoting math and science education among young girls . 
