Dear gusopol13,
Here's a footnote from the Beethoven article at wikipedia:
^1 Beethoven was baptised on 17 December 1770. Children of that era were usually baptised the day after their birth, but there is no documentary evidence that this occurred in Beethoven's case. It is known that his family and his teacher Johann Albrechtsberger celebrated his birthday on 16 December. While the known facts support the probability that 16 December 1770 was Beethoven's date of birth, this cannot be stated with certainty.
sitetest