A Danish SS sperm donor who had served in the Waffen-SS during the Second World War later became the biological father of at least 15 donor-conceived children through fertility treatments carried out at Karolinska Hospital in Sweden in the 1960s. The case, uncovered by Danish public broadcaster DR, has raised questions about how donors were selected and documented in Swedish fertility care before modern regulations were introduced.
The man was Walther Frisch, a Dane who had sworn allegiance to Adolf Hitler while serving in the Waffen-SS. After the war, he was sentenced in Denmark to one year in prison for having joined the German side.
Decades later, DNA testing has connected Frisch to at least 15 people born following fertility treatments. They live in Sweden, Denmark, Finland and Germany, according to DR’s documentary series Mysteriet om den danske nazi-donor.
At least 15 children have been linked to the Danish SS sperm donor
The known family connections have emerged through commercial DNA testing rather than hospital records. Thomas Rasmussen, one of Frisch’s donor-conceived children, discovered through genetic testing that the former Waffen-SS soldier was his biological father.
Rasmussen has since made contact with Mats Rydberg, a Swedish half-brother who shares the same biological father.
Both have questioned how Frisch, who was already in his late forties and had been convicted because of his Nazi past, could have been accepted as a sperm donor.
“How the hell can a Danish Waffen-SS soldier be my donor father? It just doesn’t make sense,” Rasmussen told DR.
The number of children could be higher than the 15 identified so far. DR stresses that the figure represents only the people whose connection to Frisch has currently been established through DNA testing. There is no reliable basis for estimating the final number.
No records explaining how Frisch became a donor
One of the central questions concerns what happened at Karolinska Hospital during the 1960s.
According to DR, neither Karolinska nor the relevant Swedish national and regional archives have been able to locate documentation explaining Frisch’s sperm donations or how he was selected.
Karolinska declined DR’s request for an interview and said it has no information about Walther Frisch in its records. The hospital added that it would be “completely unacceptable and deeply unethical” if the choice of a donor had been motivated by ideology.
The distinction is important. One of the donor-conceived children, Mats Rydberg, raises in the documentary the possibility of a connection with Nazi ideas about reproduction. However, DR has presented no evidence that Karolinska selected Frisch because of his Nazi beliefs or background.
What is documented is that Frisch had served in the Waffen-SS and that at least 15 donor-conceived children have subsequently identified him as their biological father.
Sweden’s donor rules came much later
The treatments involving Frisch took place well before Sweden created a detailed legal framework for donor insemination.
The country’s 1984 Insemination Act, which entered into force on 1 March 1985, required donor insemination to take place under medical supervision at publicly funded hospitals. Doctors were responsible for selecting suitable donors, while information about each donor had to be recorded in a special file and retained for at least 70 years.
The legislation also gave donor-conceived people, once sufficiently mature, the right to obtain information identifying their donor. That right did not apply retroactively to sperm donated before the law entered into force, leaving people conceived through earlier treatments with far fewer institutional routes for tracing their biological origins.
The absence of records in the Frisch case is therefore especially significant, but it is not evidence by itself of why he was selected.
DNA tests are exposing an obscure period of Swedish fertility care
The case also emerges against a broader reassessment of historical fertility practices in Sweden.
In recent years, SVT’s investigative programme Uppdrag granskning has documented separate cases from Swedish hospitals in which sperm was used for insemination without donors’ knowledge. Investigations have identified abuses in Uppsala, Halmstad and Norrbotten dating from the 1960s through the 1990s.
There is no documented connection between those cases and Walther Frisch. They nevertheless illustrate how DNA databases and genealogical research are now making it possible to reconstruct fertility treatments for which medical records are missing, incomplete or inconsistent.
For Frisch’s donor-conceived children, that leaves the central historical question unresolved: they now know who their biological father was, but the surviving documentation does not explain how a Danish former Waffen-SS soldier came to be used as a sperm donor at one of Sweden’s leading hospitals.
