A European fertility group is advocating for limits on the number of children a single sperm donor can contribute to, citing concerns over sibling overlap and potential health risks.

The issue comes to light as more people with donor-conceived backgrounds find hundreds of siblings through genetic testing. Ties van der Meer, who was conceived in the Netherlands, describes feeling 'problematic' about his unknown family connections.

At a conference in London, members of ESHRE (European Society of Human Reproduction and Embryology) proposed an initial Europe-wide limit of 50 families per donor. The long-term goal is to reduce this number to 15 families per donor as better data emerges on the right balance.

While enforcement will be challenging, experts argue that setting limits now could prevent future complications, including potential genetic linkages between offspring from prolific donors and the risk of unregulated donations by non-screened individuals.