In the episode Roswell That Ends Well Fry's abnormal parentage is revealed. During the commentary David X Cohen challenges viewers to describe that parentage. I would expect to see all possible answers to the question. Those answers would be:

In a predestinous universe, that is one where Fry always got some % of his DNA from himself; and in a multidimensional universe, where Fry would have at first gotten his DNA from his proper grandfather, but in all future universes somehow gets those same pieces of his DNA from himself. Also, please address the origin of his Y chromosome.

I have seen pieces of this puzzle discussed elsewhere online, however I haven't seen a fully-realized solution.

So, What percent of Fry's DNA really does come from himself? And where does his Y chromosome come from?