The 'suppression' of unwanted babies seems to have been commonplace in antiquity. Early travellers to New Zealand, while remarking on how fond the Maoris were of their children and how well they looked after them, noted that infanticide was openly practised. The most favoured methods were squeezing the nose between the fingers, pressing the fontanel, or putting a wet cloth over the baby's head-practises that time perhaps had shown would enable a child to die without a struggle.' In some Aborigine communities in Australia it was not possible for women to bring up more than one baby, and it was the duty of the maternal grandmother to ensure that the weakest of twins did not survive. Today, if an Aborigine woman has twins and one is kept in hospital requiring resuscitation, local paediatricians inform me when it goes home it is likely, in some areas, to shortly present as a cot death. Currently in China, where the state is trying to limit families to one child, there has been an increase in the incidence of cot deaths in girls-girls are being suppressed. It has been estimated that in western Europe one third of all infants were suppressed at the beginning of the last century.2 It was no chance happening that Napoleon set up large orphanages in France at that time to save infants who would form the backbone of the future armies of France. In this country the act of 1933 recognised that a mother who kills her child before the age of 1 year will not be convicted of 'murder', but of 'infanticide'. Infanticide has now a legal meaning and is associated with death under 1 year of age at the hands of the mother, but also in general it means the killing of an infant by anyone. The term 'filicide' covers the topic we are discussing, which is child homicide by either parent. We need to think of filicide in relation to the current social attitude to killing babies. The killing of a baby in utero up to at least 20 weeks' gestation can be carried out for social reasons. The question of whether or not doctors may expedite death in a viable or live born child was not solved by the Leonard Arthur case, but it is noteworthy that no further paediatricians have been brought to trial on this front. Have doctors more responsibility to individual children than parents have? We are living in a period of moving social attitudes to procreation. A quarter of all victims of legally proved homicide in England and Wales are under the age of 16-81% of them being killed by their parents; and children in their first year are at a greater risk of being the victims of proved homicide than at any other age.3 Most studies relating to filicide have been undertaken by psychiatrists working with people who have been convicted of killing their children. d'Orban,4 reporting on 89 women charged with killing or attempting to kill their own children, put the causal groups in descending order of frequency as: (1) battering, (2) mental illness in the mother, (3) neonaticide, that is the killing of a baby within 24 hours of birth, (4) retaliating mothers, (5) unwanted children, (6) mercy killing. Cases of filicide fall into two groups-newborn and later. The first present with a younger aged group of parents. These -deaths are frequently registered under the heading of 'inattention at birth'-women who claim not to have known they were pregnant, and classically the baby born into the lavatory pan. Unless there has been gross violence to the child or the child has been suffocated by a cloth being thrust into its mouth, these deaths are rarely the subject of further proceedings by the police. It is in the death of the older baby that the relation to cot death becomes important.