More identity puzzles

I don't know why I've been thinking about identity a lot lately....  But here's another puzzle:

I think what makes a person a mother at the very least is making a long-term commitment to caring for a child.  This allows us to cover all kinds of motherhood that doesn't involve biological reproduction.  Some people want to call pregnant women mothers, others, mothers to be.  Depending upon the commitment level, my definition would classify the ones who want to deliver mothers, and those that don't not mothers. 

It would also classify certain people as non-mothers that many would want to call mothers, like people who give up their babies for adoption.  I'm willing to live with this.

So whats the point of defining motherhood?  It strikes me as a puzzling kind of social identity.  E.g. I think my mom is still a mother, even though she doesn't directly care for me still (in the child rearing sense).  But what if I and my brother were to die today?  Would she still be a mother?  I'd like to say yes, since I would have called her a mother even though she's not directly caring for me still.

But the harder problems are cases where the mother has a stillborn baby.  Is she a mother?  Under my definition yes.  I suppose, others might want to take issue with that. 

Motherhood doesn't seem to go away easily once it is assigned.  Contrast that with other social identities like being a student, or an adolescent.  Even fatherhood I think is significantly different from motherhood (although I haven't quite formulated a definition for that yet). 

I'm not sure if my concept of motherhood is really robust enough either....  ambivolent mothers still seem like mothers to me, and I could imagine a mother who never makes long term commitments and simply reaffirms a short-term commitment over and over until her child turns 18, then kicks them out, deciding not to renew the commitment.

Ultimately, I find this case intresting because its another one of those cases in which we utilize a label or word without really understanding what it means in the fullest sense.  I think Socrates would be proud of my questioning.