Dutch sperm donor admits to 199 children as health ministry confirms it ignored 2017 warning

The Dutch mass sperm donor known as Simon has admitted to fathering at least 199 children, far exceeding the previously reported 121, according to a letter obtained by the news program Nieuwsuur. The 43-year-old donor from the Groningen region said 172 children were born in the Netherlands, 15 in Germany, 11 in Belgium, and one in another European country. One woman is currently pregnant. Simon claims he has stopped donating.

The admission comes as Dutch Health Minister Sophie Hermas confirmed that the Ministry of Health received a tip about Simon being a mass donor in August 2017 but took no action. In answers to parliamentary questions, Hermas said she "regrets that the parents involved were kept in ignorance and uncertainty for so long," but she did not explain why the 2017 signal was ignored. She noted that a large investigation into misconduct in fertility clinics, requested by parliament in May, will not produce results until before 2030.

Simon donated sperm through both fertility clinics and private arrangements, often using multiple names like Jesse, Johan, Daan, Sam, or Maarten. He connected with prospective parents via the internet. Many women reported that he lied about the number of children he had fathered and sent sexually suggestive messages. In his letter, Simon acknowledged: "I did not always give openness about the extent of my donation. As a result, parents have received an incomplete or distorted picture. I believed I was doing the right thing and helping people. Now I know that I have seriously failed you."

The Belgian Federal Agency for Medicines and Health Products (FAMHP) has already begun investigating possible children in Belgium. Simon is not the first mass sperm donor in the Netherlands. The practice raises risks of half-siblings unknowingly entering incestuous relationships later in life.

Minister Hermas dodged questions about why the 2017 tip was not acted upon, especially since shortly before, signals about two other donors (including mass donor Jonathan Meijer) were actively investigated. Former minister Edith Schippers declined to search the fertility clinic registry for potential mass donors in 2017. As a result, Simon continued donating for years, and even served on the advisory committee evaluating the new donor law in 2019 — a fact Hermas now "regrets."

For the technically literate audience, this case highlights systemic data-tracking failures. The Netherlands has a national donor registry, but it was not cross-referenced with private donation networks or multiple aliases. The ministry's inability to act on a clear signal in 2017 points to gaps in how fertility data is monitored and shared across clinics and jurisdictions. The investigation promised by 2030 may propose regulatory changes, but the timeline raises questions about whether the government is taking the issue seriously.

Source: NOS: Massadonor Simon schrijft aan ouders, NL Times: Dutch mass sperm donor Simon says he has 199 children, NOS: Minister komt met onderzoek zaaddonatie