What does it mean to be Human?

Been thinking about humanity again.  I've been thinking a lot about humanness. The situations of these past several years, droughts, famine, natural disasters and responses to them.  But re-thinking in the wake of Michelle Bachmann's unthoughtful comments about the HPV vaccine (of which I'm not entirely a fan) make me think again about humanness.  What is human?  Is it just biology? Because we don't always treat people we say are human beings as 'one of us'.  Maybe if aliens landed we would have some sort of moment where we would realize that we all are the same species, but until then we have so many ways to divide and codify who we are - - and who we are not - -  to one another.  If vaccinations don't work, why is there no more polio?  Shouldn't we look at what the world was like before vaccines?  This is not to say I don't have reservations. But it's the same as genetically modified foods: on one hand, certain gm foods could save people's lives by creating seeds and produce that can be grown in areas that have difficulty growing things.  But - - and it's a big but  - - do we want one or two companies owning the seeds that allow us to eat?  Is humanity connected by greed or is it connected by compassion or are both in play depending on who it is, what a person's class status is?  With vaccinations, should an individual who believes vaccinations are bad be allowed to  put others at risk because they refused to vaccinate against measles?  Or are we standing up for our beliefs and individual freedoms by saying "no" because we are unsure of the veracity of statements that drug companies tell us; knowing also that a lot of researchers and doctors don't take time to deal with, learn and research efficacy of "natural" or holistic modalities.  Is nuclear power clean and efficient and thereby safe to be located near people's homes only until a complete Chernobyl type meltdown when, of course, we suddenly acknowledge just how dangerous radiation is?

Though these things may seem like unrelated issues, they feel related to me because they deal with how humans actualize the concept of humanity, or lack thereof, by creating otherness.  Who decides who is worthy for care?  Who decides what is a worthy cause?  Who decides who are the good and bad people, the angels and the derelicts, the family men or the pimps?  Who decides?!  Who is human?  What does the word really mean?