Thesis 6 is about the fact that humans are bi-gendered for the sake of procreation, so humans can multiply and flourish themselves. They are gendered not just for multiplication but also for mutuality, for relationship, a one flesh relationship that only a male and female can share. Scot discussion of ezer kenegdo is right on target (pp. 134-35). It means a suitable helper, and since God himself can be called the helper of Israel (Ps 121.1-2), the term implies no subordination of one party to the other (p. 138). Adam found no such helper amongst the animals, only in Eve, his equal in the image of God.