I agree with you Sydey, that biographies should be accurate, but taking information straight from the subject constitutes original research and since we can't see their identification papers it's not verifiable.
How do you suppose we verify the correctness of a given birthdate if there's no newspapers or books stating the date the subject says is correct.
It occurs to me that in academia, one occasionally sees "personal correspondance" or "publication forthcoming" cited. Is there something wrong with stating "The New York times gives Jim Smith's birthday as 24 May 1964, although Jim has stated that it's 24 May 1965[1]" where [1] is Personal email to Wikimedia Foundation, 5 Nov 2005. It's verifiable in the sense that you could always email Wikimedia and ask them if that's true.
Steve