Sales of "misery memoirs" or "vic lit" generated over £24m in profit last year and show no signs of abating. Supermarket shelves are overflowing with sagas about the nasty things parents do to their babies, toddlers and children - many with one-word titles that sum it all up: Ugly, Abandoned, Betrayed. Yet, in the public arena, when it comes to deciding who is the guilty party, so often, it's the mother who is given the benefit of the doubt. This hypocritical idolisation of motherhood is a killer - for all concerned.

According to a study published in the current issue of the British Medical Journal, murder should never be ruled out when investigating repeat cot deaths, in spite of claims that most are natural.

The study conducted by two retired paediatricians, Christopher Bacon and Edmund Hey focus on a paper published in the Lancet two years ago that suggested that almost 90% of repeat cot deaths were natural - contrary to the view expressed by paediatrician Professor Sir Roy Meadow that two cot deaths are highly suspicious and three almost certain evidence of homicide.

Sir Roy's evidence was given in the case of Sally Clark, convicted of killing her two sons then freed on appeal in 2003. He had said that there was "a one in 73 million chance" of two children dying from cot death in the same affluent family. The Lancet study looked at 46 repeat cot deaths. It classified 40 as natural, six as unnatural - that is murder or manslaughter.

Bacon and Hey have reclassified the cases into three categories - probably natural, probably unnatural (including six homicides) and undetermined. According to the new classification, 43% of the deaths are undetermined and may be the result of violence from parents or others. The authors of the study point out that this fits with earlier studies that suggested about 40% of repeat cot deaths were homicides.

The authors say:

"Uncertainty may be uncomfortable but it is truer to reality, more conducive to scientific inquiry and safer for children than a dogmatic stance at either pole. Experience in child protection teaches that it is often impossible to determine whether the parents have been in some way and to some degree responsible for the unexplained death of their baby."

Safer for the children ... and yet. Joyce Epstein from the charity, the Foundation for the Study of Sudden Infant Deaths, said on Radio 4's Today programme on Friday that the category of "undetermined" would be upsetting for parents. Frankly, so what?

It must be horrendous to lose a child to a cot death, but if a parent has had no part in a child's demise why should the category "undetermined" be troublesome? Surely that would add an extra spur to research to divine the causes?

Three hundred babies a year die from cot deaths - half of which are from unexplained causes. Genetics, sleep patterns, unknown ailments and infections may explain some in this category but others do die at their parents' hands. In the US in the 60s, one mother killed five babies, all declared cot deaths, until she confessed many years later. A one off, or a glimpse at a compulsion that is a well-concealed pattern in the population?

Report after report has called for a much more efficient response in the immediate aftermath of cot deaths including the skilled accumulation of evidence and statements, paediatric post mortems and lengthy examination of the history of the family. None of which has yet materialised systematically and nation wide. Why? Perhaps, in part, because we cling to the notion that mothers can do no harm?

Some mothers, to gain attention, can and do suffocate their babies to the point where they lose consciousness. How often does the tactic go too far and become an unexplained cot death? Some women inflict damage or invent symptoms for their healthy offspring to attract the attention of the medical profession. See Sickened by Julie Gregory. Published sales in this country have reached half a million so far. Why do we believe what we read between hard covers when often the considered views of paediatricians (and many are cautious in extreme in their judgments) are rejected out of hand?

Mad or bad or deeply traumatised - whatever the motive, such women are a danger. And, until society removes mothers from the pedestal of eternal innocence, children will die.