Some children have a LOT of trouble with writing because they are using the wrong hand! It happens. A left handed child may attempt to be like everyone else, and use his right hand to write. In fact, very intelligent kids can make this mistake, because from a young age they notice that we live in a right-handed world, and thus they copy everyone else. They use the right hand, instead of doing what comes naturally. These children have a very difficult time getting the words onto the paper, they are slow and sloppy, disoriented, and they may end up failing to thrive in school... and no one knows why.
I recently met with a mom whose son had this problem. Instead of teaching him to use his left hand, the doctor encouraged the parents to let him use a computer and type out his schoolwork, rather than use a pencil and paper. He was only a second grader at the time, but this seemed to work well.
After hearing this story the mom showed me a little test the doctor did with her son. To see if he was right or left handed. I tried the test and realized that although I grew up right handed, I have many left handed tendencies. That evening I decided to put a pencil into my left hand to see if I could draw. Well, my left hand surprised me!
Look what I drew with my left hand:

I just gave my left hand a chance to draw for the 1st time! Here are my first few drawings. I have always used my right hand until now.