My ditto and mewtwo have been in the daycare a week and no egg! What is wrong?
Mewtwo is in the Undiscovered Egg group, and as such cannot breed. So that means no egg for you from those two.
http://pokemondb.net/mechanics/egg-groups/undiscovered
No, they can't. Any Pokemon that's in the undiscovered egg group cannot have eggs. Hope This Helped :D