Korean people have a 13 digit resident registration number respectively in Korea.
The first 6 numbers are date of birth.
So many mothers want to get the number started 111111....... for their children.
The appointments of delivery are 20% more than average.
Some mothers have an expected date around November 20th.
Nowadays, C-section is not dangerous as much as before.
However, you have to do C-section for 2nd, 3rd children if you did for first child.
Which means the mothers' bodies are no longer natural condition.
I can not recommend that unless in case of necessary.
20% more children will be born is meaning many classmates of the kids' may have same birthday.
And hard to see 11/11/11 if it is a hand writing (ﾟー^*)d