The problem with that is that it violates the separation of church and state and promotes a religion through a government institution. If we teach a pseudoscientific theory about how GOD made everything and such and such, there will have to be other religious alternatives. They'd have to teach all creation myths and not just the one from Genesis. If parents want their kids to know about how god created everything, they can teach them themselves. Rather than enlisting help from the school system.
It's much more simple to stick to what we can prove and observe, and let the individual decide themselves.