I have a feeling that the kind of cultural winds that would blow away the stigma of selling babies would also knock down our conception of the family (and I’m very impressed with my own imagery here). The special status we award to genetic relatives is probably some sort of product of our place and time, with a healthy dose of biology, but since the same could be said about the taboo of selling children, there is no reason to act as if in the absence of one, the other would necessarily hold true.