Whole Genome Sequencing (WGS) in newborn screening is ethically complex. Parents will provide proxy consent for initial participation and 16-year-olds will be approached to consent to continued storage of their genome. We explored the views of 11–25-year-olds to understand the information needs of this age group and the views of the next generation of parents. This two-phase UK study involved: a secondary analysis of focus groups with young adults and a diary and focus group study with children with CF. Diaries were analysed using content analysis, focus group data were analysed using reflexive thematic analysis. Diaries illustrated how children formed genomic knowledge and their questions. Participants broadly supported WGS-NBS based on a belief that all results improve health. Pre-study knowledge was sometimes correct, other-times it drew on vicarious ideas that could cause distress. Children showed an ability to appreciate the complexity of deciding which results should be returned. Focus groups: All participants counterbalanced the benefits and risks of WGS-NBS. Children demonstrated innate trust in doctors, whereas young adults wanted parent-doctor collaboration in decision-making. Young adults conditionally supported WGS-NBS depending on treatability, severity, onset and consent. Children wanted parents to be informed of a broader range of results, but valued informed choice too. More research is needed to understand healthy children’s views. Although small samples, this work provides insight into the understanding and concerns of young adults and children which could help when trying to discuss this topic with them.