The Happiest Day - Happy Birthday Card for Son: This perfect cupcake birthday card will put a smile on your son's face for his special day. The frosting with blue sprinkles makes this cupcake irresistible! But the best part of this birthday card is the loving message that expresses that the day your son was born was the happiest day of your life. So special! Let your son know how dear he is to you by sending this meaningful birthday card to you him today!