If you are making a parallel between your parenting and God's commandment to His creation (Adam and Eve), you have to put it in the right context. God's commandment could be equivalent to you telling your child to not jump off of a bridge that will lead to certain death. It isn't about harshness, but the consequences of the action taken. In the case of Adam and Eve, spiritual death would be the consequence of disobeying God and eating the fruit from the Tree of the Knowledge of Good and Evil.
Likewise, if your child were to disobey you in jumping off of a bridge in disobedience, it too would lead to their death. Its not being stringent or harsh, its coming to grips with the reality that our actions have consequences, good or bad.
My father raised us with this in mind. Yes he laid down ground rules, taught us the Bible, right and wrong, but ultimately he let us know that we have the freedom to choose but know that there are consequences to your actions. In this way he wasn't holding anything back from us, as often such leads to rebellion, but rather allowed us to weigh our options and make an informed decision.