In SEX DIFFERENCE EXPLAINED: From DNA to Society – Purging Gene Copy Errors, Steve Moxon argues that all major aspects of male-female human sociality necessarily stem from biological principles; which all arise in solving the core problem faced by all life-forms: the relentless build-up of mistakes in the repeated copying of genes. The 'genetic filtering' to deal with this is the function of the male: why males came into being, and why men so fiercely compete with one another to form a hierarchy.
The female contribution is carefully to choose only the most dominant/prestigious males, cross-checking that indeed they do possess the best gene sets. This ensures genetic mutations and other errors that would seriously compromise reproduction are purged from the local gene pool.
Pair-bonding serves to exclude lower-ranked, whilst allowing access by still higher-ranked males; and to provide a serial father of children, thereby in effect projecting forward in time a woman's peak fertility, compensating for her deteriorating store of eggs, and consequent declining fertility and attractiveness.
With men tied to a hierarchy, women evolved to 'marry out' to avoid in-breeding. In preparation for this, girls have a very different social organisation, rehearsing for when later they have to make close bonds with non-kin, stranger-females for mutual child-care. This explains why female grouping is so tight and exclusionary, whereas males group all-inclusively.
Moxon sees the underlying sex dichotomy as being perfectly complementary, with the sexes of equal importance in what amounts to a symbiosis.