Placenta

Okay, so my cousin just had a baby and she had her little sister cut it up and make it into a smoothie.  Whatever.  But as I read other people discussing this, I got to wondering, who's placenta is it?  Is it the mother's or the baby's?

My instincts say it's the baby's because it is inside and I thought that the blood supply was for the infant.  When I learned about blood types and the problems a mother could have if her kid had a different Rh factor (I forget which way), I thought that there was some sort of barrier so that the mother's and infants blood didn't mix very much at all.

On the other hand, it was the mom who ate the food that went into making it- the baby couldn't do it on her own, and really what good is a placenta to a newborn?  But if I kept on with this logic, it seems like the mother could eat her child if she wanted to because she is the one who "grew" the baby.  OF course, this is absurd, because babies can live outside while placentas cannot.

Anyway.  Just thought I'd share.