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.
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 all born in August.
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.
- Now, it is considered to be in the free public domain.
February 29 born
- Do they celebrate only in Leap Years?
- Do they celebrate on February 28 or March 1st?
Different Calendars
Some celebrate their birthday twice : once using the Gregorian Calendar and once using the Myanmar luni-solar Calendar.

Categories: Concept