Previous research showed that intersex people face specific challenges in their sexual development, including uncertainties or confusion about their gender, a negative genital self-image, and hesitance to engage in romantic and sexual relationships. However, in-depth knowledge of a central period of this development, adolescence, is missing. In our qualitative study, we explore which factors influence the relational and sexual development of intersex youth and what elements contribute to a positive development. We interviewed eighteen intersex persons aged 18-38. We identified three main themes: (1) intersex experiences, (2) the described sexual and relational life course, and (3) factors influencing a positive development. Our findings show that intersex youth face many obstacles to their relational and sexual development, many of which related to healthcare. However, their life stories also illuminate how healthcare professionals but also parents, friends, partners, teachers and others can make a substantial difference in intersex lives by breaking normative, binary thinking on sex and gender.