Résumé : AbstractBackground: In Western countries, many children are affected by the separation of their parents. Our mainobjective was to assess the possible impact of parental separation family structure on certain aspects of somatichealth in low-age children.Methods: We conducted a cross-sectional study based on data collected in the framework of free preventivemedicine consultations in the French Community of Belgium. The data was derived from assessments conducted,between 2006 and 2012, on children 7 to 11 months after birth during which information of 79701 infants wascollected regarding the risk of sudden infant death, psychomotor development, and development in terms ofheight and weight. The main outcome measures were: episode of risk of sudden infant death, polysomnography,home monitoring, psychomotor development, and body mass index.Results: The parents of 6.6% of the infants were separated. We established multivariable models, based on thepresence or absence of confounders. The adjusted ORs (95% CI) of symptoms perceived as frightening, notably atnight, of a prescription for a polysomnography, of an abnormal polysomnography result, and of follow-up by homemonitoring were thus respectively 1.3 (1.1–1.6), 1.1 (0.9–1.3), 1.8 (1.3–2.4), and 1.3 (1.1–1.6). The adjusted ORs (95% CI)for psychomotor delay and for a body mass index above the 97th percentile were respectively 1.3 (1.0–1.6) and 1.2(1.1–1.3) in the event of separation.Conclusions: This study confirms the possibility that not living with both parents is an independent risk factor for thesomatic health and psychomotor development of infants. This observation should be verified because it would have amajor impact on the actions of family doctors and other first-line healthcare providers, in particular with regard toinformation and targeted prevention.