What exactly is a child?
The definition of "child" is different in various cultures. To many peoples around the world, 13 is the age of maturity. In our culture today many people refer to twenty somethings as children, whereas 75 years ago or so a very large part of the population got married in their early teens. Many 12 year olds are physically mature, and in some cultures far more mature emotionally than they are in the US.