When registering for GW2, I noticed right when I signed up and the page was loading, I noticed that I didn't input my birthdate correctly, I sent a ticket about it, but is there really any use other than verifying your not 5 years old? Is it even stored? Or just used as a one time verification?
It might be a piece of information that A-Net will ask for to confirm that you are the rightful owner of the account should you account get hacked or some other problem arises.