Why limits to gamete donor use only work if they cross borders

When a Dutch court ordered a sperm donor to stop donating in 2023, at least 550 people had already been conceived using his sperm through several clinics, sperm banks and private arrangements (see BioNews 1188). Two years later, it emerged that gametes from a donor carrying a rare de novo cancer-predisposing variant had been distributed across 14 countries and used to conceive at least 197 children, some of whom have since developed cancer (see BioNews 1291 and 1319).

These cases have attracted a lot of media attention, but it would be a mistake to see them simply as failures of individual clinics or of donor screening. They are the predictable consequence of a commercial system in which gametes move freely across national borders but the rules governing their use stop at those borders.

Due to the importance of this topic, the European Society of Human Reproduction and Embryology (ESHRE) has produced a position paper on international limits on the number of offspring per gamete donor. This was published in July 2026 in Human Reproduction and sets out ESHRE's position on how many families should be created from one donor.

Most European countries have a limit on the number of offspring or families that can be created from a single donor, but those limits vary widely, are not consistently enforced, and, importantly, count only what happens inside one jurisdiction. Cross-border treatment and the export of donor gametes are routine: in the UK, 57 percent of new donors in 2024 were from imported sperm.

In Belgium, the Federal Agency for Medicines and Healthcare Products carried out an audit in 2025 due to their national limits on donor use being exceeded, and found widespread use of imported gametes in Belgium and donors used across many jurisdictions (see BioNews 1308 and 1335). A sperm donor can comply with every national rule and still have over 100 genetic offspring spread across Europe alone.

This matters because what is important for donor-conceived people is the total number of donor siblings they have, not the number who live in the same country. Indeed, a donor may have more offspring in a small geographical area in another country than in their own. Therefore, a limit that counts only domestic births is measuring the wrong thing, and the ESHRE position paper argues that a transnational limit is the only mechanism that can address this issue. The paper calls on the European Union (EU) to introduce an EU-wide limit as a feasible first step, supported by an EU-wide donor registry to monitor compliance.

The ESHRE position paper recommends that limits be expressed in families rather than individual children. Counting families protects recipients' ability to use cryopreserved embryos they have already created and allows parents to have subsequent children with gametes from the same donor. This is something many families want, whether to strengthen sibling bonds or to limit the number of donor relationships their children may have to navigate. Counting children would make a family's own reproductive planning hostage to how many births had occurred elsewhere.

ESHRE proposes a phased approach to the reduction in donor use: an immediate Europe-wide limit of 50 families per donor, reduced over time to a maximum of 15 families or lower, alongside a cap on distributing gametes to new families more than 20 years after a donor's first donation. We acknowledge that a fifty-family limit for donors is too many, but it is a starting point, and already represents a substantial reduction on current limits, with some banks operating self-imposed caps of 75 families and others none at all. The suggestion of a transition period gives banks and clinics time to adjust without excessive disruption to patients in treatment.

Donors face a parallel difficulty: responding meaningfully to dozens of approaches is not realistic, and the implications for their own children are not trivial.

This all creates uncertainty, the gradual, open-ended discovery of more siblings with no way of knowing where this ends, and, for some, a sense of having been mass-produced. The published evidence base underpinning the recommendations is thin, but growing, and the position paper recognises this.

Contact between donor siblings is often experienced as positive and rewarding. But discovering a very large sibling network can be overwhelming and difficult to navigate, and some donor-conceived people who have no wish for such relationships find themselves contacted regardless. Hence, although definitive 'scientific' evidence of harm is limited, there is also no reassuring evidence that very large sibling groups are unproblematic. Further, donor-conceived people, unlike donors, cannot be asked to consent to the conditions of their conception. Given all this, we take the view that a precautionary approach is justified.

Donor limits were historically justified by fears of consanguinity, but modelling suggests the risk is very low, and lower still where siblings are geographically dispersed; increased openness within families and widespread direct-to-consumer genetic testing reduces it further. Nor do limits address the population prevalence of genetic disease – for any individual recipient, the chance that a donor carries a serious condition is unrelated to how many families that donor's gametes reach (see BioNews 1352). What limits and time caps do affect is the number of people harmed when something is missed, and a registry makes tracing those affected possible.

The first version of the paper went out for stakeholder review in November 2025, generating 45 responses from organisations representing donor-conceived people, patient and family organisations, national societies, researchers, clinicians and gamete banks.

The position paper was debated in a panel discussion at the 2026 ESHRE conference in London, with contributions from Professor Carlos Calhaz-Jorge (former chair of ESHRE), Dr Maciej Śmiechowski (chair of Fertility Europe), Ties van der Meer from Donor Offspring Europe, Nick van Gelder (Belgian representative on the SoHO Coordination Board) and Ole Schou, the founder of Cryos sperm bank.

The great majority of stakeholders and speakers supported international limits, and most supported 15 families or fewer as the ultimate aim. The notable exceptions were the gamete banks, and in the panel discussion, Schou argued that such limits would raise prices due to a reduction in available donors.

This is a concern. Fewer families per donor means more donors are needed. Without rapid expansion of the donor pool, waiting times and prices will rise, inequalities in access will widen, and more people will turn to unregulated private donation, with the potential medical and legal risks that carries. This is why the position paper also recommends a call for an increase in donor recruitment and a phased implementation.

For a UK readership there is an obvious question. The ten-family limit set by the Human Fertilisation and Embryology Authority (HFEA) applies to treatment in licensed UK clinics; sperm donated here and exported is used under the rules that apply at its destination, and imported sperm could have been used in other countries to create families. The HFEA has said this falls outside its remit. Whether UK regulation should require clinics to apply an international family limit for donors is a question that now needs to be addressed.

In conclusion, a Europe-wide limit is important. Leaving it to national regulators has not worked, and there is no reason to expect it to start working now.