Can a minor visit his father in a Missouri prison if the father is a offender?

I'm a little unclear about the answer to this question as I have found conflicting statements. My husband is in prison at JCCC, but for driving while revoked, not for his offense. He seems fairly certain that our 3 year old son cannot visit him unless he is 18 or older simply because of his prior offense. My oldest would like to visit him as well, but he is only a step-son which I figured would be less agreeable. From what I have found, that relates to the child we had together, is that I can submit a visiting form along with his birth certificate and hope for the best. The prison family handbook mentions children visiting offenders only briefly and merely states that physical contact is usually strictly prohibited, not that they would not be allowed to visit at all. So, I am completely confused. If anyone has some REAL incite or experience in this area it would be appreciated greatly.