The 41-year-old from The Hague has allegedly fathered at least 550 kids around the world. According to the foundation's lawyer Mark de Hek, the donor violated agreements with the clinics and with the prospective parents, who relied on his commitment to only conceive up to 25 children. "When a donor's genetic material is present in a large number of offspring, the (very small) risk that two half-siblings might form an intimate relationship is increased", PET highlighted