There were many time for birthday, also to about two, three months, wife had to worry about her husband's or her son’s birthday.
Then husband worried for birthday wife and children, and children worried for parents lucky day.
Only one person, no one worried to - elderly grandfather.
And until one day - the day that the grandfather died.
The husband asked his wife: When is his birthday?
The wife asked her husband: When was he born?
The children asked their parents: Which month was he born?
So the children, grand children, great - grand children have to go find his birthday in the birth certificate as the identity problem for his tombstone.
It's the first and the last birthday.