Naive human embryonic stem cells: the new contender?

Recent breakthroughs have described the production of human embryonic stem cells which resemble more the mouse counterparts. These stem cells possess a naive state of pluripotency, in contrast to 'primed' stem cells which show already some differentiation. Different culture protocols enable the derivation of naive human embryonic stem cells, but the question remains which protocol gives rise to the similar naive pluripotency state as in mice.