Birthday

by Hla Min

Updated : Aug 2025

Twins

Most twins share the same birthday (Day, Month, Year).
An exception occurs when one twin is born before midnight and the other is born after.
Another exception occurs when one twin is born on New Year’s Eve and the other is born on New Year.

February 29 born

Do they celebrate only in Leap Years?
Do they celebrate every year on February 28 or March 1st?

Same Month

If there are more than 13 people, then at least two must share the Month in their birthdays.
It follows the Pigeon Hole Principle.

Same Month and Day

If there are more than 30 people, then there is a high likelihood that at least two share the Day and the Month in their birthdays.
It follows from Probability and Statistics.

Distribution

In a group, the birthdays are not equally distributed. For instance, my two sisters and I are August born. There are seven siblings.

Freebie

Some restaurants do not charge the Birthday Person (Boy, Girl) if there are three more persons in the group. They will ask and verify the ID.

Happy Birthday

“Happy Birthday” song is one of the most played songs. In the early days, the song received a lot of royalties. It is now in the free public domain.

Different Calendars

Some celebrate their birthday twice : using the Gregorian Calendar and the Myanmar luni-solar Calendar.