The traditional family, as we have known it, is ripe for transformation into something phenomenally different. The pressures created by families may be imploding under their own weight . . . So wrote an obscure philosopher last century. He failed to mention that some of the family's functions, particularly those to do with child-rearing, had served society well for millennia. Why? Are we programmed for this by genetic endowment?

Modern Cassandras, examining statistics on divorce, single-parent families, and working mothers, also forecast imminent social collapse. But children do not become social passively; they are actively involved in forming attachments, as are their parents. There are many differing patterns of child-rearing, many equally valid.

In thinking about the family, we should also remember other alternatives which have been tried. In the former Soviet Union, deliberate hierarchical attempts to subvert the family's networks of loyalties and love failed grossly. The Kibbutzim in Israel have not substantially changed family relations, have not proved popular, and have had several unfortunate side-effects. Most other alternatives in communal living have not succeeded as intended, or have been short-lived.

The happy arrival of a first-born infant may be divisive, launching disagreements between husband and wife, and enmities anywhere in the extended family. The first major stirrings of disharmony can precede the birth. To have a child, or not? Clearly, reliable contraception has changed the social ecology of the couple. Or should they postpone the birth for better circumstances or solid relationship? Different outlooks on such issues can be traced back to the kinds of relationships that existed between prospective parents and their own parents.

For mothers-to-be, that which they felt they lacked in their lives makes them want these things for their child. Women who experienced an early parental loss are especially vulnerable.

Changes within the new mother are often of a physical nature, and her concerns highly practical. More than ever, she needs sensitivity, and feels she deserves to be at the centre of her husband's attention. A woman may wish that, by having a baby, she can assert herself, compete with her mother, or become immortal.

Mothers are always more responsive to the immediate needs of their babies. The maternal bond could be the strongest one of all. The human infant needs far more nurturing, for comparatively longer. The mother's intense responsiveness seems to emerge right away, and probably reflects a protective biological sensitivity. Once aroused, it is long-lasting.

On the other hand, most husbands have retained most of their patriarchal thinking. Their initial feelings are of love, pride, and sometimes, jealousy. The new mother may well seem entranced and in love with the infant. To the man, the birth has an important symbolic and role-related dimension, signifying yet another responsibility, one with implications for his family's future. But couples who were more psychologically involved in sharing their experiences, who were close to one another before the baby was born, report feeling more positive about the delivery and the baby.

The first pregnancy is a normal developmental crisis for both parents-to-be. Soon after the baby is born, there are complex and delicate mother-father-baby interactions. Anything that can be done to improve the self-confidence of the parents, also helps the infant. Thus, emotional support from the extended family is invaluable to them, the mother especially; they obviously have a great wealth of appropriate experience.

The moods and temperaments of both parents play an integral role in this subtle system. As many as 80% of newly delivered women are affected by transitory post-natal low moods. Although usually one of the milder forms of depression after child birth, it can still be disruptive to the family unit. In some mothers, there is a feeling of lacking well-being; they are easily irritated, tense and fatigued. Around 15% lose their desire for, or enjoyment of, sexual intercouse, typically only in the short-term. Usually in these cases, the husband observedly does precious little if anything to help with the baby, and tends to cope less well with disagreements in general.

However, important research at America's National Institute of Child Health has recently detailed that 62% of fathers also experience depressed mood at some point within four months of the birth. This adversely affects their behaviour too. Fathers who reported eight days or more of low mood addressed fewer words and sounds to their babies. They were more physically distant and emotionally aloof, and in the way of these near-balletic interchanges, the mothers compensated by heightening their proximity, increasing their care-giving, and by reassuringly touching the babies more frequently.

By the time the babies were a year old, there were other differences. Mothers who had infants who were insecure or avoided parental contact more, would express more negative feelings toward their babies. This occurred whether they were observed at home or in the psychology laboratory's novel environment, a small room with toys. But they were more positive towards their babies when their husbands were also present and helping.

In whatever setting, when mothers and babies were securely attached to each other, the mother was more likely to engage the baby in a more playful and stimulating way. This means good parents are continually learning how best to fulfil their role. In doing this, they still need to remain true to themselves, with individuality and joint goals. It would be a hollow victory if they produced great children, but in the process sacrificed their ideals or love. Good families clearly also retain much hope for their futures.

l Dr David Weeks is a clinical neuropsychologist and co-author of Superyoung (Hodder Headline, #9.99).