Maybe when Lex became an orphan at 13/14 he went and got a woman pregnant, and that was where Jaxon came from. Such could happen.
I always got the impression that Lex had only admitted to Lois about one previous child, and about no marriages. So there may well have been a child killed in a car accident along with said child's mother, but that was not neccesarily Jaxon.
