What was the most number of wives Mormon founder Joe Smith had at one time and how old was the youngest?

Being "sealed" as a spiritual wife isn't quite the same thing as a normal marriage. Many of Joseph Smith's "wives" were only sealed to him, and not actually married to him. We know who he was sealed to, but we don't know who he was actually married to. All of his known children came from Emma. Today, a wife is both married and sealed to their husband, but back then it was possible to be married to one, and sealed to another. In fact, it is still possible. A widower will often marry a second wife, and remain only sealed to the first.