 The investigators propose to set up a single-centre, descriptive, transversal pilot study, designed for the inclusion of around thirty children from 2 to 10 years, with haemophilia or allied hereditary bleeding disorders HBD, who were referred to the Hemophilia Treatment Center HTC of Marseille at diagnosis. For those children who were able to benefit from the totality or part of the device accompanying the diagnostic announcement in the past 10 years. 