STUDY QUESTION: How should the number of offspring per gamete donor be regulated at an international level? SUMMARY ANSWER: The European Society of Human Reproduction and Embryology (ESHRE) recommends introducing a European Union (EU)-wide limit on the number of families per gamete donor, starting at 50 families and gradually reducing it to a maximum of 15 families or lower, supported by an EU-wide donor registry to monitor compliance. WHAT IS KNOWN ALREADY: Most European countries impose national limits on the number of offspring or families per donor, but these limits vary widely and are not always enforced. Cross-border movement of patients and the export of donor gametes between countries mean that large donor sibling groups can still emerge despite these restrictions. What matters to donor-conceived people is the total number of donor siblings, regardless of which country they are in, making a transnational limit the only relevant mechanism that can address this issue. STUDY DESIGN, SIZE, DURATION: This position paper sets out principles relevant to international donor offspring limits and the position and policy recommendations of ESHRE, focusing on the EU level. PARTICIPANTS/MATERIALS, SETTING, METHODS: This ESHRE position paper was developed by a multidisciplinary expert working group. Recommendations are supported by data from the literature, where available. The first version was published for stakeholder review in November 2025, with 45 completed review forms received from organizations representing donor-conceived people, families built through donor conception and infertility patients, national fertility societies, researchers, professionals from different disciplines, and gamete banks. The paper was then revised on the basis of the stakeholder review. MAIN RESULTS AND THE ROLE OF CHANCE: ESHRE considers that the wellbeing of donor-conceived people should have the highest priority when determining limits, while also balancing the wellbeing of prospective parents. Limits should be set for the number of families rather than individual children. ESHRE proposes a phased introduction starting at 50 families per donor, being reduced to a maximum of 15 families or lower, alongside a 20-year cap on distributing gametes to new families after the first donation. National limits should still be upheld where they are lower, and donors should be able to set their own lower personal limit. Compliance should be monitored through an EU-wide donor registry or, failing that, national registries, with gamete banks (including non-EU banks exporting into the EU) obliged to enforce the limit, donors required to declare all previous donations, and families counted as potential live births unless confirmed otherwise. LIMITATIONS, REASONS FOR CAUTION: The evidence base on the psychosocial impact of large donor sibling groups is small and developing, and definitive evidence of harm is limited. Research on the preferences of donor-conceived people, donors, and recipients regarding offspring limits is scarce and inconclusive. These recommendations therefore take a precautionary approach, and the proposed 15-family limit should be reviewed in light of developing knowledge during the transition period. WIDER IMPLICATIONS OF THE FINDINGS: An EU-wide limit would represent a feasible first step towards an international limit. An EU-wide donor registry could potentially serve secondary purposes such as supporting tracing in case of the diagnosis of a serious genetic condition and giving access to information to donors and donor-conceived people. FUNDING: Support for the working group was provided by ESHRE. DISCLOSURES: L.F. and C.C.-J. report travel support from ESHRE. D.P.B. reports speakers' fees from Merck, Ferring, Gedeon Richter and MSD, travel support from ESHRE, and a position as the president of the Croatian Society for Gynaecological Endocrinology and Human Reproduction. A.A. reports speakers' fees from Merck Healthcare KGaA and Ferring, travel support from ESHRE, passive shareholder interest in Inception Midco 1. S.à r.l., membership in a subgroup of the European Medical Devices Coordination Group, and a position as vice chair of the EXPAMED panel on obstetrics, gynaecology and reproductive medicine. G.N. reports speakers' fees from Gedeon-Richter and Organon, travel support from ESHRE, and a position as past chairman and member of the Executive Committee of the Bulgarian Association for Human Reproductive Embryology. P.T. reports speakers' fees and travel support from Ferring and Gedeon Richter and a position as a board member on the Arbeitskreis donogene Insemination. J.K.-B. reports speakers' fees from Ferring, IBSA, Merck and CooperSurgical, travel support from Merck and ESHRE, an associate editor position for the journal Andrology, and a position as chair of the scientific advisory committee of the Association for Reproductive and Clinical Scientists (ARCS). The remaining authors (J.T. and N.V.) have nothing to declare. TRIAL REGISTRATION NUMBER: n/a.
Frith et al. (Wed,) studied this question.