Why Do We Say CHEESE, When Cheesy Is What We Get?

I have always thought that I was a very fortunate mother! My son and now daughter both have a big beautiful smile. You know how you always see those young children in photos who have that comical smile that you can't help but notice? My children have never had one of those smiles, unless of course they're just acting silly. Well that is until now! Nathan recently had his first school pictures taken and being a mother you have to order those! In doing so I realized that sometime between the age of 4 and 5 almost all children temporarily loose the ability to smile normal! This ailment seems to affect males more then females. So at this point I'm asking myself is there a cure? How long will this last? All of course while laughing and praying that Lilli does not come down with this strange disorder! ........Then again these are the pictures that high school graduations are made of!