BackgroundThere are no studies identified that address professionals' knowledge of sexual behaviour problems in children aged 0-12 years. However, it seems essential for child professionals to be able to identify the healthy or pathological nature of sexual behaviour.Case presentationWe proposed a cross-sectional, descriptive and comparative observational study using anonymous questionnaires distributed to medico-social professionals in France. They were questioned on their knowledge of normal sexual development, risk factors for developing sexual behaviour problems, and the future of minors presenting these behaviours.ConclusionsAmong the 93 respondents whose questionnaires were usable, there were 12 men and 81 women. The majority of respondents didn’t know the age at which psychosexual and emotional child development begins (73.1%) or didn’t know the age limits for sexual behaviour problems (95.7%). Very often, these professionals represented children with sexual behaviour problems as "children who have been abused" (81.72% of respondents) and/or who "will become child perpetrators of sexual violence" (70.87% of respondents). All these answers highlight the lack of training of these professionals, at the risk of proposing a reply that is not adapted to children with these disorders. So, it seems essential to offer more systematic and adapted courses to professionals who take care of minors in institutions.