She didn't know his birthday or his middle name.
I had no trouble in remembering that - everyone knows his own birthday.
She did not even know her son's birthday.
I know my birthday by heart, but anything other than that is touch and go.
The dates must be written down, so that nobody knows anyone else's birthday.
Say that you do not know your birthday, and people may be shocked.
But there is something about knowing one's true birthday that goes beyond legal necessity.
He knew your birthday, too, not just the year, but the day and the month.
The child will never know its own birthday.
How would you know my father's birthday if he had not been of special interest to you?