A European fertility group is pushing for international limits on sperm donations, arguing the current free-for-all is producing distressing outcomes for donor-conceived people. The issue: without caps, a single donor can end up with hundreds of biological children scattered across the world. One Dutch man’s sperm was used to conceive between 550 and 600 kids. While anonymous donation is banned in many places, home DNA tests from companies like Ancestry and 23andMe have made it trivial for donor-conceived people to uncover their genetic relatives — sometimes finding dozens or even hundreds of half-siblings. The proposed solution is a Europe-wide limit on the number of children per donor. Beyond the emotional toll — one woman described feeling “mass-produced” — there are real risks: unknowing incest, and the potential for passing down harmful genetic mutations, as happened with a Danish donor whose sperm led to at least 197 children despite a known cancer-linked mutation. Why it matters: As reproductive technology goes global, the lack of coordinated regulation is creating sprawling, unacknowledged genetic networks that challenge our notions of family, identity, and consent.