From the NYT:
"Pakistan’s largest political party picked Benazir Bhutto’s 19-year-old son to succeed her as chairman and vowed to forge ahead with elections next week."
Sure, why not pick a 19-year-old? How old was Alexander when he succeeded Philip? How old was Pitt the Younger when he became Prime Minister?
It's the blood that matters. (Or just the name -- next door in India, Sonia Gandhi, the widow of Rajiv, daughter-in-law of Indira, and granddaughter-in-law of Nehru, led the Congress Party to victory in the last election, even though she's an Italian ex-stewardess and doesn't really speak any Indian languages well.)
My 2003 National Interest article on the trend back toward dynasticism is here.