Happy Day, night or hour of which you left your mother's womb via the front door or by getting cut out, or the other way.
OR Happy day of which you were successfully created in a lab, you genetically engineered son of a gun.
Remember, you may have the appearance of someone else but inside you are very your own person!
That got randomly deep.... Happy Birthday.
"Finish what you started human!" - Kamaji from Spirited Away