Family communication about adult-onset hereditary illness can be problematic, leaving some relatives inadequately informed or ignorant of their risk. Although studies have explored the barriers and facilitators in family communication about genetic risk, questions remain about when, what, how and indeed whether to tell relatives. The process of disclosure is also dependent upon the way in which genetic information is realized and understood by recipients, but research here is limited. Our paper explores young people's experiences of finding out about a family history of the hereditary disorder Huntington's disease (HD). In-depth interviews explored how and when young people found out, their reactions to different communication styles and any impact on family relations. We recruited young people through the North of Scotland regional genetics clinic and the Scottish Huntington's Association (SHA). Thirty-three young people (aged 9-28) were interviewed. A qualitative analysis was undertaken which revealed four types of disclosure experiences: (1) having always been told, (2) gradually told, (3) HD was kept a secret, or (4) HD as a new diagnosis. In particular, the timing and style of disclosure from relatives, and one's stage of awareness, were fundamental in structuring participants' accounts. This article focuses on questions of when, how and indeed whether to tell children, and sits within a broader set of research and practice issues about what professionals and families (should) tell children about parental illness and genetic risk.