Adolescents and young adults (AYAs) with cancer, aged from 15 to 39 years, are making the transition from childhood to adulthood. When the burden of cancer is added, it becomes part of this extraordinary and challenging time in their growth and development. Cancer affects the psychosexuality of AYAs as well as intimate relationships, which in turn influences their well-being. However, the discussion on sexuality and intimacy is hard to initiate, and AYAs are not satisfied with the information provided by the healthcare providers. The project looked into the big picture of sexuality and intimacy care for AYAs in the Netherlands and the unmet needs of AYAs. Based on the research findings, the design concept is developed. It is an online application together with a website. To tackle the problem of insufficient discussion, the application gives information about the disturbances and prepares AYAs to initiate the discussion with their healthcare providers. For AYAs’ dissatisfaction with the information supplied, the project looked into AYAs’ unmet needs and constructed an information architecture that covers their needs. Literature study and interviews were conducted in the research phase. The design phase implemented iterative design and human-centred design approaches, where AYAs were kept at the heart in the process.