Spasticity is usually caused by central nervous system injuries, such as brain injuries or spinal cord injuries. Spasticity is a little different from stiffness.
As your child with CP is becoming a teenager, there are a couple of things you may want to think about.
To give you an idea about genetic variation between each of us, there are about three million differences in our genetic code. They go to influence the color of our hair and the color of our eyes, the way we walk.