Once upon a time paternity was about whose genes had been passed on to whom. Paternity has now become synonymous with fathering in the way that maternity has always been synonymous with mothering.
Bringing up children is a struggle for both parents. That often means fathers are concerned enough about upbringing to run to baby care gurus such as Sheila Kitzinger and Penelope Leach, just as mothers do. And guess what? They are just as dissatisfied with the answers.
Hence a book like this, from a father's perspective 'that tells it the way it is'. Yet the ambivalence of fatherhood never really gets thrown out with the bath water. It is intense, but not quite as intense as motherhood. And unlike maternal instinct, paternal instinct has more to do with pride and self worth - 'The feeling of being a father, though: that was terrific. Away from any sort of social pressure or middle-class ritual - in fact, on my own, whenever possible, without even the distracting presence of the baby - it was a fantastic sensation', says Jennings.
Nonetheless, a badge of honour is not enough. New Dads at least have to be seen to be trying - easier now disposables have replaced towelling nappies that Jennings insists no dad, new or otherwise, would ever go near.
As they muck in, New Dads have discovered what mothers have known all along - a huge gap between parenting and parenting theory.
No one seems prepared to tell you about the drudgery, the inane parent-child rows, the struggle to civilise the uncivilised - also known as child rearing - and the sheer boredom and thanklessness of a large part of it.