The 'natural' is not necessarily a 'human' value. Humanity has begun to transcend nature: we can no longer justify the maintenance of a discriminatory sex class system on grounds of its origins in nature. Indeed, for pragmatic reasons alone it is beginning to look as if we must get rid of it.

The Dialectic of Sex: The Case for Feminist Revolution (ed. Farrar, Straus and Giroux, 2003) - ISBN: 9781466833517