A former professor at Harvard Medical School and founder of one of the nation’s largest fertility clinics is being accused of secretly impregnating a patient in 1980 after promising the sperm would come from an anonymous donor, according to a lawsuit filed Wednesday.A former professor at Harvard Medical School and founder of one of the nation’s largest fertility clinics is being accused of secretly impregnating a patient in 1980 after promising the sperm would come from an anonymous donor, according to a lawsuit filed Wednesday.