When photographing your kids, it's a good idea to vary your shots. One thing you can do is focus on one body part. (D)SLRs lenses, especially faster ones with a low F/stop allow you to throw out of focus other elements of the image. As the eye will naturally look at the in-focus part, the subject of your picture will become immediately clear, just like with this shot.
Sometimes it's the very pose that make the shot endearing, just like this one where Kaz is practicing his snake kung fu.