DNA tests never really settle the question 100%. Here's a new theory about King Tut's ancestry:
http://www.heritagedaily.com/2013/02/egyptian-archaeologist-shares-...
"French Egyptologist Marc Gabolde offered a different interpretation of the DNA evidence on Thursday. Speaking at Harvard’s Science Center, Gabolde said he’s convinced that Tut’s mother was not his father’s sister, but rather his father’s first cousin, Nefertiti."
