March 21st - the 21st day of the 3rd month of the year
This is the date chosen as World Down Syndrome Day because Down syndrome is a result of 3 copies of the 21st chromosome (Trisomy 21).
On to the reason we celebrate. Micah has started to scrunch up his nose and do an open-mouth smile when you ask him to give his "cheesy grin." It's hilarious!