Miggrator
>_>
I share my birthday with Aizen....
Somebody shoot me now...
D:! No, we shouldn't.
Besides that...
As a note, these aren't their REAL birthdays... it's stated in a side story:
"To the people who grew up in Rukongai, birthdays don't really exist. If you're born into royalty over here it might be different."
"...we're all the same. No one actually remembers the exact date of birth. you just have to trust the date that someone tells you."
Also, Matsumoto's birthday definitely isn't such - it's stated that her birthday is the day she met Ichimaru. ^^