Fertility doctor Kaarbat used own sperm and fathered 105 children, more than assumed

Fertility doctor Jan Karbaat, who died at age 89 in 2017, used his own sperm to father at least 49 children with clients who used the fertility clinic he worked at. After five years, it has now become clear that Karbaat has fathered up to 105 children. This figure was confirmed by the Donorkind Foundation, which campaigns for the interests of donor children. For the oldest Karbaat child, Annerie Meul from Eindhoven, it now means that they are now "105 half-brothers and half-sisters", she told Omroep Brabant.

The head of a former sperm bank secretly inseminated dozens of women with his own sperm. Karbaat donated his sperm mainly in Brabant and outside the Dutch border. "He exchanged sperm with all hospitals in Brabant where this type of treatment was done. Karbaat also had many customers from Brabant in its clinics," said Ties van der Meer of the Donorkind Foundation told the newspaper.

In 2019, a group of children filed a civil lawsuit in order to gain clarity about the man who fathered them. In February, the court in Rotterdam ruled that Karbaat's DNA could be used for testing.

Karbaat's daughter Annerie is shocked by the addition to the family, as she had not expected so many half-siblings. With 56 additional half-siblings, the "little club" of siblings from five years ago has grown immensely. As a result, she no longer feels like having siblings.

She says that Karbaat had a massive impact on the gene pool in the Netherlands. And not in a positive way. "My youngest brother, who I know so far, went to high school with my daughter. They were only three years apart. They could have had a relationship. That's what I worry about," she told Omroep Brabant.

For years, Jan Kaarbat donated his sperm and demanded that no one from his ranks tell anyone else, allegedly for the child's sake. According to the foundation, Kaarbat was "the first doctor in the Netherlands from whom we received confirmation that he had used his own sperm."

However, it has since been proven that there are a further 11 clinic employees in the Netherlands who donate their own sperm. This has resulted in 60 or 70 children for some, but most donors have fathered fewer than ten children, according to Van der Meer.

The only sperm donor in the Netherlands who has fathered more children than Karbaat is sperm donor Louis with 109 children.