.
According to the letter to Hebrews, a Melchizedek high priest must be
childless. That alone disqualifies most Mormon men because they're typically
married with children.
In addition: Melchizedek high priests have to be human, but at the same
time they cannot be someone who came into existence by birth. In other
words: Melchizedek high priests always were, they always are, and they
always will be, i.e. they have no genealogy to trace.
This is problematic because the current Melchizedek high priest is Jesus
Christ; a Jewish man who can be easily proven not only human, but also
easily proven that he came into existence by birth, and also has a genealogy
that can be traced.
Were Jesus Christ only human, he would not qualify for Melchizedek high
priesthood. But we know from John 1:1-14 and Hebrews 3:3-4 that Jesus
Christ is also divine. This may seem like a trivial issue but according to the
New Testament's letter to Hebrews; in order for someone to be an effective
mediator between God and Man, he has to be both human and divine.
I seriously doubt that there's even one sensible Mormon man anywhere on
Earth who would dare lay claim to being both human and divine. Those are
some really big shoes to fill.
_