What is a Normal Family?

In children's textbooks it is defined as Father, Mother and Child.

I refuse to adhere to that thinking. It is a social norm that a family should be composed as such. A social norm is not a natural law, but rather a common instance, so much that it is considered as such. But this should not be so. A family is simply a group of people who live and love under the same roof. That's all there is to it.