Abstract STUDY QUESTION Which decision-making factors influence family building among permanently infertile couples? SUMMARY ANSWER Ethical, legal, and financial considerations outweigh genetic relatedness in decision-making, favouring domestic gestational surrogacy, if this were possible, over international options. WHAT IS KNOWN ALREADY Permanent infertility affects 4–5% of people in the fertile age. Their family-building options include adoption, surrogacy, uterus transplantation, foster care, and intentional multiple parenthood. However, in most countries, including Denmark, legal barriers constrain these methods due to surrogacy restrictions, suspended international adoptions, and the experimental status of uterus transplantation. Despite existing research on surrogacy, adoption, and specific causes of permanent infertility, a significant gap remains in our understanding of how couples with permanent infertility make family-building decisions within these limited frameworks. STUDY DESIGN, SIZE, DURATION This cross-sectional study with 150 permanently infertile Danish participants was conducted from June to November 2023 using an online questionnaire. Multiple strategies, such as online forums, fertility clinics, hospital departments, and snowballing, were used to recruit a diverse sample. PARTICIPANTS/MATERIALS, SETTING, METHODS The study included couples aged 26–50 years facing permanent infertility due to the following primary causes: women without a uterus (15%), women with a non-functional uterus (47%) or women for whom pregnancy would be life-threatening (9%), male couples (16%), transgender partner couples (2%), and other causes (11%). The survey collected data on demographics, reproductive history, family-building choices, and communication strategies. Closed questions were analysed using descriptive statistics. MAIN RESULTS AND THE ROLE OF CHANCE Among 150 respondents, 41% had used transnational surrogacy, 27% adoption, 14% chose to remain childless, and 19% were undecided. Critical factors on family-building decisions were ethical, legal, and financial concerns which ranked higher than genetic relatedness. Despite the complexity of family building, most participants were open about their child’s origin and received social support. If all family-building methods were legal and available in Denmark, domestic gestational surrogacy would be the preferred method, with uterus transplantation and remaining childless being least popular. LIMITATIONS, REASONS FOR CAUTION The sample size is relatively small, despite the use of a variety of recruitment strategies. Nevertheless, this has ensured a diverse cohort representing the different reasons for infertility and family-building choices. It is important to note that the strategies may have favoured individuals achieving parenthood. WIDER IMPLICATIONS OF THE FINDINGS The finding of our study reveals a notable gap between available family-building options in Denmark and the preferences of couples facing permanent infertility. These insights could be instrumental for organizations reviewing and developing family-building frameworks. Furthermore, for healthcare professionals guiding couples experiencing infertility issues in their attempts to build a family, an understanding of these preferences is essential to facilitate informed decisions about their future family plans. STUDY FUNDING/COMPETING INTEREST(S) The project was financed by the Independent Research Fund Denmark. The authors have no conflict of interest to declare. TRIAL REGISTRATION NUMBER N/A.