however, more or less in the form of sexual irregularities or immorality
among all peoples; more often, however, among the civilized than among
the uncivilized, but among no people has it ever existed unqualified by
more enduring forms of sex relation. Moreover, because promiscuity
breaks up the social bonds, throws the burden of the care of children
wholly upon the mother, and lessens the birth rate, we are justified in
concluding that promiscuity is essentially an antisocial practice. This
agrees with the facts generally shown by criminology and sociology, that
the elements practicing promiscuity to any great extent in modern
societies are those most closely related with the degenerate and
criminal elements. Those elements, in other words, in modern society
that practice promiscuity are on the road to extinction, and if a people
generally were to practice it there is no reason to believe that such a
people would meet with any different fate.

_The Earliest Form of the Family Life in the Human Species_,
therefore, is probably that of the simple pairing monogamous family
found among many of the higher animals, especially the anthropoid apes,
and also found among the lower peoples. This primitive monogamy,
however, as we have already seen, was not accompanied by the social,
legal, and religious elements that the historic monogamic family has
largely rested upon. On the contrary, this primitive monogamy rested
solely upon an instinctive basis, and, as we have seen, unless children
were born it was apt to be relatively unstable. Permanency in family
relations among primitive peoples depended largely upon the birth of
children. Thus we find confirmed our conclusion drawn some time ago that
family life rests primarily upon the parental instinct. That it still so
rests is shown by the fact, as we shall see later, that divorce is many
times more common among couples that have no children than among those
that have children.