Sex in Genesis 1:26-31 and 5:1-2

Martin Davie observes that, taken together, these two accounts make six points about the creation of humankind.
First, we learn that human beings do not exist by chance. God, who created the universe in general, also decided to create human beings in particular and…everything that God creates is ‘very good’ (Genesis 1:31), including the human race.
Secondly, we learn that God created human beings as male and female from the beginning…
Thirdly, we learn that it is as male and female that human beings are the image and likeness of God…In God’s kingdom…the special role he has assigned to humanity is that we should serve as his ‘under-kings,’ vice regents or stewards. We are to rule over the creation so that God’s reputation is enhanced within his cosmic kingdom…As embodied souls, humans have the capacity to know and love God, each other, and creation as a whole; therefore we can fulfil our God given vocation to exercise God’s rule. Men and women have this capacity and vocation on an equal basis, [and] they are called to do so together as two indispensable halves of the human race.
Fourthly, we learn that there is an analogy between the existence of human beings as male and female and the life of God himself. In Gen 1:26 God says, in the plural, ‘Let us make man in our image, after our likeness.’…There have been many attempts to account for this use of the plural, but the explanation that appears most consonant with both the immediate context and the analogy of Scripture identifies the usage as a plural of fullness…The use of the plural with reference to God’s creation of humans as male and female points to a correspondence or analogy ‘between this mark of the divine being, namely that it includes and I and a Thou, and the being of man, male and female.’
Fifthly, we learn that part of the human vocation to live as those made in God’s image and likeness is obedience to the divine command in Genesis 1:28: ‘Be fruitful and multiply, and fill the earth and subdue it; and have dominion over the fish of the sea and over the birds of the air and over every living thing that moves upon the earth.’
[Sixthly], to be male and female in God’s image involves having male and female bodies. Being male and female is not just about having a particular kind of consciousness derived from our immaterial soul. The soul is what allows us, like the angels, to have conscious personal relationships with each other and with God, but in order to share in God’s work of creation and to obey his mandate to be ‘fruitful and multiply’ human beings also need to have sexed bodies designed for both sexual intercourse and procreation.
Glorify God in Your Body (abridged and reformatted)