Well according to a loony British cardinal.
Those of us who have sneaking transhumanist tendencies might wonder why being human is so great anyway. When nutty religionists come out with pronouncements like this, we might feel the temptation described by PZ Myers:
There is a temptation to agree with them, I'm afraid: the idea that I'm a post-human mutant bestowed with the super-powers of reason and the ability to see through superstition is flattering. But it's not true. Everyone has those powers, it's just that some of us have had the good fortune and a history of experience that allows us to shake off some indoctrination. Nothing more.
Well, yes, I pretty much agree with this. But usually when authoritarian personalities formulate the idea that some fellow Homo sapiens are "not fully human" it implies that they are sub-human - not just in their capacities but in their moral worth. It's a bit frightening when representatives of powerful organisations start to speak like that.
And note that Cardinal Cormac Murphy O'Connor is the same guy who is after a seat in the House of Lords. If I have any UK readers, I hope you're campaigning against this guy obtaining any temporal power.