The contemporary valuation and normalization of the nuclear family is a very recent development, even among modern populations.
For Native Americans, modernity began in 1492.
Very much more recently than this,
the nuclear family structure became the modern norm,
and even more recently,
the modern nuclear family became so highly valued that it was baptized by modern hybrid and hyphenated-American Christian religions.
The modern nuclear family is now christened "traditional," "Christian," and inaccordance with "family values."
The contemporary family of so-called traditional Christian family values and moral prescriptions are:
(1) not traditional,
(2) not biblical, and
(3) not actual or possible or desirable in practice.
(2) There is nothing in Christian or Hebrew scriptures favoring nuclear family households over extended and tribal structures. To the contrary, biblical families are overwhelmingly extended-tribal families instead of nuclear families.
(3) Moreover, without recourse to oppressively cheap or slave labor, or to extraordinary wealth with which to purchase significant help from outside the nucleus, this way of living is not even possible.
for as long as we are committed to modern education-socialization processes which sustain the now normal 15+ year gap between biological readiness for sexuality-procreation and sociological readiness for marriage-sexuality-procreation;
prescribing sexual abstanance until after a sociologically ready marriage amounts to prescribing 15+ years of celibacy for whole generations of biologically ready humans.
No human people could (or should) succeed in imposing such behavioral strictures upon itself or others..