Another reason why I asked the question is I'm an only child. Born in the spring.
There was no sharing of birthday with other siblings who may have been born on a day close by.
Rarely my birthday would be on Easter, if we had an early Easter.
Everyone who knows me knows I don't share a birthday! As I grew up got married and had a career, when it came time to celebrate birthdays with friends & family I made it clear -- not just for me but for anyone -- sharing a birthday is a no no.
This is how strongly I feel about it. When I was carrying my DD, I went into labor on her dad's birthday but refused to deliver her until the next day. I was under a doctor's care, I didn't risk her life but she was not coming into this world until the next day. She always understood this growing up, kind of an inside joke within the family. I think because of this, she will make sure her son is sufficiently celebrated on Christmas. She'll just have to work out the details.