Not surprisingly, such presumptions often risk invoking the wrath of a feminist establishment that has never been very comfortable with the implications of evolutionary theory. Indeed, to many feminists it appears to symbolise the male urge to totalise at its unimaginative worst. Virginia Woolf warned that "Science ... is not sexless; she is a man, a father, and infected too". Yet according to Sarah Blaffer Hrdy, an anthropologist and primatologist at the University of California, the "genderscape" of the natural sciences has been transformed by a massive influx of women at the highest levels of research since the 1970s, when she trained. These women, she informs us, together with some of their male counterparts, are redefining evolutionary science both in terms of the data they amass and the interpretations they place on it.
Over the past century an overwhelmingly male community of evolutionary thinkers tended to swallow whole the model, first posited by Darwin, of the passive, nurturing female and the active, domineering male. Darwin himself was merely articulating a myth implanted by Rousseau and further cultivated by the Victorians. He even went as far as to proclaim that "whether requiring deep thought, reason or imagination, or merely the use of the senses and hands [man will attain] a higher eminence ... than can woman".
And yet, as Blaffer Hrdy points out, this dichotomy between the aggressive male and the passive female is a false one because it misconstrues the way in which the so-called "maternal instinct" works. In fact, by using evidence from a wide variety of sources - historical, anthropological, literary and mythological - she shows that our whole concept of motherhood is in desperate need of revision.
To begin with, she insists, mothering is invariably more about planning strategies and making deals than it is about nurturing and self-sacrifice. Her book is packed with revelations about the simmering undercurrent of tension between females of all species and their offspring. In humans, it seems, from the moment a child is conceived it is struggling to extract as much from its mother as it can without killing her. Hence at every stage of the development process, from conception, to birth, weaning, and the emergence of competitive siblings, a constant trade-off is taking place which will profoundly affect the child's personality.
Psychologically, Blaffer Hrdy draws heavily on the ideas of the late John Bowlby, whose attachment theory remains clouded with controversy because of feminist fears that it further endorses the "enslavement" of mothers. Blaffer Hrdy modifies it, however, by establishing, in a series of chapters on biological features such as the foetus, the placenta, and the process of lactation, that the pendulum of power swings both ways. Indeed, the infant's biological needs are in direct conflict with the mother's so frequently that it appears the battle of the nursery is even more virulent than that of the sexes.
If anyone doubts this proposition they need only read the chapters on infanticide and child-abandonment to see Mother Nature at her most calculating and pitiless. Most disturbing of all is the way in which Blaffer Hrdy argues that the prevalence of infanticide is one of the great medical cover-ups of our time. "Many millions of infant deaths", she observes, "can be attributed directly or indirectly to maternal tactics to mitigate the high cost of rearing them".
At this point one might be inclined to suspect that Blaffer Hrdy is yet another sociobiologist on a mission to reduce the world to a set of conflicting, robotic interests. And yet, she insists, her purpose is not to destroy our faith in humanity but to restore it. Her central point is that by falsely sentimentalising motherhood we risk neglecting something more important: the needs of the infant. Perhaps somewhat disingenuously she adds that a new non-nurturing view of motherhood would remove what Adrienne Rich called the burden of the "G-spot", where the mother feels overwhelmed by "judgements and condemnations, the fear of her own power, the guilt, the guilt, the guilt".
But more optimistically Blaffer Hrdy provides examples from other species and cultures to show that mothers can effectively manage dual careers. By stressing the full diversity of human and animal behaviour she is reminding us of our capacity for conscious choice, a choice which we neglect at our peril. Moreover, she never suggests that genuine female self-sacrifice does not occur in nature. At one point she cites the moving case of a woman who, after three marriages, two miscarriages, and a stillbirth, became pregnant while suffering from leukemia. She opted to have the child but died after delivering a healthy baby.
Perhaps if there is a flaw in this book it is a certain confusion about why fathers, particularly modern fathers, aren't more involved in childcare. Intriguingly, Blaffer Hrdy suggests that small differences between the sexes have been magnified by a modern obsession with allocating roles, but then, paradoxically, reverts to a more conventional sociobiological refrain about innate differences. However, this is a splendidly thought- provoking book which will undoubtedly establish its author as the alpha- female of evolutionary thinkers. With one great stride Blaffer Hrdy has carried the debate about parenting to a higher stage of adaptation. It should be required reading for parents, feminists and evolutionary scientists alike.