In case that is true, he'd better walk around with a 'Midlife-Crisis' tattoo on his forehead.
Anyway, mentioning one's birthdate is not a crime nor even an invasion of privacy. In fact, anything that's written on your ID card is subject to public knowledge. Legally, you can't hide such information about yourself. Many artists use pen-names and pseudonyms and have pretentious whims concerning the revelation of their real age, heritage and such, but in the end, they have no legal right to prevent anyone from publishing that. If the information is innacurate or untrue, however, then that's the only case the authors can be accused of difamation.
(this is the law in my country, don't know about the US, though)