Last night when I got home, DH told me about a conversation he had earlier with his mother. DH is the eldest of 3 sons, he's 53 and they were all born reasonably close together.
Apparently they had a conversation along the lines of how old was youngest son this year as it was his birthday last week, is he 50 now or was he going to be 50 next year. Apparently DH's dad couldn't remember either.
Now I know it's been approximately 50 years and you can't remember every detail, but surely you should know your own DC dates of birth?!