The death of the nuclear family

THE 20TH century has spawned an institution - the lone-parent family - destined to change the face of society. One in five children already lives in such families in Britain and the United States and everywhere the proportion is increasing. Soon, lone-parent families - over 90 per cent of which are lone-mother - will replace the traditional nuclear family as the social norm.

True, lone-parenthood currently has undesirable consequences on average for both mother and children: survival, health, fertility, performance at school and delinquency rates all suffer. But a disadvantageous past and present do not necessarily herald a disadvantageous future - because biologically the environment is changing.

Lone-parent and nuclear families are biological institutions that form under certain conditions and disintegrate under others: whatever moralists, traditionalists and legislators might wish. Nuclear families form when females need male help in raising offspring and males can protect sexual access and paternity only via mate guarding. Then mutual fear of both infidelity and desertion becomes biological cement that binds couples together. In humans, mothers are vulnerable to being left destitute, men to cuckoldry. Make either less vulnerable and biological bonds can weaken, eventually to the point where both sexes prefer lone-parenting.

Why have lone-mothers often struggled in the past to match their nuclear counterparts? The answers are obvious - weaker finances and elusive, unaffordable day-care. It is not lone-motherhood per se that causes the problems, but the lack of money and help. Children do not suffer from the simple absence of a live-in male. Nor does how long a live-in adult male is missing make any difference.

We should not be surprised; we should not exaggerate a man's traditional contribution to parenthood. Of 80 non-industrial human cultures in a world survey, fathers were "rarely" near their infants in 18 and were "close" to them in only three. A man's main contribution to successful parenthood is not via his presence or masculinity but via the resources he generates.

There are two main groups of lone-mothers: those who are the victims of rape, desertion, or separation and those of independent means who choose lone-parenthood, are happy with their situation, and can afford to raise their children without disadvantage. Currently, the former, more vulnerable, group is in the majority. Over the next few decades, though, the second group should mushroom - because the main factor that has recently changed and will change even more is the level of women's financial dependence on living with a man.

Which brings us to a modern irony. The crusade for Child Support enforcement had an undeniably punitive element, aimed at making men suffer who left their families. In all the polemic, it was expected that Child Support legislation would pressurise nuclear families into staying together. In the hands of biological urges, however, Child Support and the increasingly associated Paternity Testing have the opposite effect. No longer will a woman need to tolerate an inept, perhaps violent, and increasingly undesirable man simply to avoid becoming destitute. Child Support legislation will see to that. No longer will a man need to spend his life with a woman simply to guard against cuckoldry. Paternity Testing will see to that. Biological cement will crumble and couples will simply separate once initial feelings of love and excitement disappear.

Today, the lone-parent lobby is a minority voice, but it is growing louder and will soon crescendo. Eventually lone-parents will become the bulk of the electorate; governments will become their hostages. From that moment, lone-parent families - and the blended families that arise when lone-parents cohabit - will become the social norm, heralding a new era in human social evolution.

Robin Baker is author of `Sex in the Future: ancient urges meet future technology' (Macmillan, pounds 12.99)