A single Dutch sperm donor is estimated to have fathered between 550 and 600 children. A Danish sperm bank unknowingly used a donor carrying a cancer-risk mutation in at least 197 children, some of whom developed cancer, some of whom died. In the United Kingdom, more than half of all sperm used in fertility treatments in 2020 was imported from abroad, where donor limits may differ or not exist at all.
These cases have prompted Europe’s leading reproductive medicine society to call for the first continent-wide limits on how many families a single sperm or egg donor can serve.
The European Society of Human Reproduction and Embryology (ESHRE) published its position statement on July 8, proposing an initial limit of 50 families per donor, with a long-term target of phasing down to 15 families. The limits are voluntary, ESHRE is calling on fertility clinics and sperm and egg banks to adopt them, but the organization hopes they will provide a unified standard in a field where national regulations vary wildly.
A Patchwork of National Rules
Currently, donor limits across Europe range from 1 child per donor in Malta and Cyprus to 10 families in the UK and 12 in Denmark. But these national limits are easily circumvented. A recipient in a country with strict limits can order gametes from a clinic in Denmark, the world’s largest sperm exporter, where the donor may already have children in dozens of families. The donor’s total, across all countries, becomes untrackable.
“In the age of cross-border fertility care, national limits don’t mean very much,” said Jackson Kirkman-Brown of the University of Birmingham, commenting on the proposal. “We need a European framework.”
The Consanguinity Problem
The core concern is the rising probability that donor-conceived half-siblings, who may number in the hundreds for a single donor, could unknowingly meet, form a relationship, and have children. This risk increases as donor-conceived children grow up and enter the dating pool.
The issue has gained urgency as direct-to-consumer genetic testing allows donor-conceived people to discover half-siblings their parents may not know exist. “It does make you feel a bit mass-produced,” one donor-conceived woman who found 25 half-siblings told MIT Technology Review.
The Meijer Case and Its Aftermath
The most extreme example is Jonathan Meijer, a Dutch sperm donor whose sperm was used to conceive an estimated 550 to 600 children across multiple countries, aided by multiple clinics. A Dutch court ordered him to stop donating in 2023, but by then the damage, if it can be called that, was done.
The Meijer case exposed a regulatory gap: no single authority tracks how many children a donor has fathered across borders. ESHRE’s proposal is an attempt to fill that gap, not through legislation but through voluntary compliance by clinics and egg banks.
Reactions and Open Questions
The proposal has been broadly welcomed by donor-conceived advocacy groups, but questions remain about enforcement. Without a central registry that spans European countries, clinics would need to rely on self-reporting by donors and information-sharing between banks. The phased approach, starting at 50 families, then moving toward 15, gives clinics time to adapt.
Researchers who study the psychological well-being of donor-conceived people have noted that the number of half-siblings matters beyond the consanguinity risk. Vasanti Jadva of City St George’s, London, told MIT Technology Review that donor-conceived people who discover large sibling networks often report feeling overwhelmed by the scale. “There is a psychological dimension,” she said. “Finding 50 or 100 half-siblings is a very different experience from finding four or five.”