The facts of assisted reproduction: between biological essentialism and social constructivism

In assisted reproduction it is ordinary to co-produce both the social and biological facts of kinship. In contexts of assisted reproduction biological facts don't define univocally a kinship relation. They need legal conventions to define the ambiguity produced by the biological facts. In assisted reproduction kinship is a relationship defined by agents' intentionality who want to be parents, but alienation and objectivation of body-parts are necessary for the bio-medical reproduction of kinship. Taking into account that the standard theory of kinship has been set up by the distinction the natural facts of reproduction and the social construction of them, which are the implications for kinship theory of the co-production of the social and the natural? Taking into account that agents' intentionality is opposed to the objectivation and alienation of body-parts, what does it mean a bio-medical reproductive mode that necessarily objectifies the parts of the reproductive body?