Today is my brother's birthday. The Boy is 2 years and a day younger than me. My parents thought this would be a great idea. (And explained to me later how difficult it was to plan... ew)
All sharing a birthday really did, though, was ensure I had to share my birthday party with him until I was 12. This meant a lot of bowling. I beat him up a lot for this until he outgrew me when he was 14.
It has also meant that I get a lot of "Happy Birthday"s one day late. People tend to remember his birthday and then go "Oh, no! Bronwyn's was yesterday". Yeah. Way to steal my spotlight. Turd. Like always.