So there was this guy named Leonardo da Vinci, and he did some pretty great things. Just about everyone ever thinks he was one of the biggest geniuses in history, and that he changed the world. During his life, he said this:

"Nothing can be loved or hated unless it is first understood."

When it comes to parenting and education (which are the same thing half the hours of the day), I think we've got to get what Leo said right. We have to teach our kids to suspend judgment until they actually understand something. Then, once they understand it, the next step is to show them that they really don't, they've only understood what they want to understand. They should hit the books again. They should talk more with their teachers and mentors, especially those who will challenge their thinking. Then they can get busy having some sort of opinion.

The main point is that we all think we understand something, but it sometimes turns out we might not. "The one who states his case first seems right, until the other comes and examines him" (Prov. 18:17). This is part of the core of a good education.

But there are a few caveats, as usual:

When it comes to ultimate or foundational truths, such as God, creation, good and evil, and the nature of man, we should teach our kids that truth is divinely revealed (Ps. 19), not figured out just by man's reason from a supposed tabula rasa. We should teach our children to study God's truth (2 Tim. 2:15), not blindly accept it, but that without first having the Light of Christ, there is no knowledge.
Teaching our kids to see all sides of an issue, and to challenge their preconceived notions, is not the same thing as teaching them to be lifelong skeptics. It is not the same thing as teaching them to thumb their noses at tradition and values-based thinking, and to view true enlightenment as holding no opinions whatever, unless they are the opinions of the currently-in-vogue academic elite. That is the way of nihilism and sorrow.
Once we have taught our kids to see all sides of the issue, all while seeking Christ as the ultimate guiding Principle, we should teach them to decide one way or the other. Chesterton said that a mind is like a mouth: it is designed to eventually close on something.
Once we teach our kids' minds to close on something (which is not the same thing as being close-minded), we should never inadvertently teach them to avoid controversial opinions simply because they are not popular opinions. Part of love is not being needlessly antagonistic in our thinking; but part of courage is always saying what we think is right.
Our kids should learn to be exposed to different or offensive opinions without being offended. This is good practice, because Paul reminds us that the Gospel is offensive to those who don't believe -- and yet we must love both the Gospel and those who are offended by it.

In short, our kids should be like Leo, and be like Christ.