The Secret Service is getting a historic change at the top: President Obama has picked the first woman to lead the agency, reports the Washington Post. Julia Pierson, 53, began working as an agent about 30 years ago and eventually moved up to her current post as chief of staff. Part of the reason Obama picked her is that he wants to change the macho-man culture that has led to messes such as last year's prostitution scandal in Colombia, says the Post. The pick, which does not need Senate confirmation, is expected to be made public today, reports AP. (More Secret Service stories.)