In the UK, the ethics of engaging in sociological research directly involving children have primarily been shaped by definitions of "competence". While this has been a crucial guideline for researchers in shaping the concept of informed consent, it has also acted, perhaps inadvertently, as a way of excluding particular children from the research agenda. This article discusses the problems of informed consent that were encountered in research with children with learning impairments. It proposes that the process of seeking "assent", when used within an ethical framework, is a more comprehensive method of gaining the agreement of children in research, which transcends language, ability, cultural, social and international borders.