The reason for this Mitzvah is to recognize how great G-d is. The best way to see how great G-d is, is to examine his creations. Studying Science is a tremendous Mitzvah when we actively look for G-d's existence in his creation. The closest and most convenient study of creation is to look at ourselves. Human beings are the most interesting of G-d's creation and at home you have a whole house full of them.
Child development is one of the most interesting subjects to discuss.
Look at how a helpless baby who can not fend for itself takes as much as 20 years to become independent. Human beings are very smart yet human babies are more helpless than any other animal. Think about how great it is that G-d created babies with limited intellect. It could have been very possible for G-d to create babies with perception and understanding. This would be cruel as the baby's body's are incapable of control.