You taught your child to walk, dress himself, use silverware, identify colors, and myriad other skills long before he turned five. You are already an expert at teaching your child. There is no reason to think that you can’t also teach him to read, do addition, and anything else he needs to learn.
You care far more about your child than a classroom teacher (no matter how dedicated) ever will. You can spend more time one-on-one with your child than a teacher can. You can choose materials specifically for your child’s learning style, instead of forcing your child to learn from the generic books that the school board happened to select. You are the person most qualified to customize your child’s education.
Those who earn teaching credentials take classes to learn how to write lesson plans. They take courses in educational philosophy, classroom management, testing methods, and content-area teaching tips. These are good things to study, but it is not necessary to earn a teaching degree to be a good teacher or provide a quality education to your child. If any of those topics interest you, visit a university bookstore and purchase the textbooks required for the teacher-ed courses.
Some people object to the parent-as-teacher, claiming that there are things that kids need to learn that the parents don’t know. The obvious response is that if it was necessary for people to know it, you would know it. It is far more likely that a desired subject will come along that the parent doesn’t know about – in which case the parent can learn alongside the child, or the parent can hire a tutor for the child, or the child can do research and teach himself… Resources abound.