The age of maturity of children to consent for medical research is under debate, as different authorities regard the capacity of young teenagers as either satisfactory or not to grant consent without parental participation in the process. The present paper contrasts the generally accepted guideline for ethics in paediatric research in Canada with what the same children are allowed and expected to be able to do as babysitters. This comparison reveals deep incongruences in the way the maturity of the same (...) children is appreciated for two different tasks. (shrink)