A Danish SS soldier was a sperm donor in the 1960s thanks to Sweden's Karolinska hospital. He is the biological father to at least 15 children who now want to know if they are the result of an ideological racial project. They are both deeply astonished that a man in his late 40s, who was convicted for his pro-Nazi opinions, could end up being a sperm donor in Sweden. AdvertisementIt’s currently impossible to say how many children Walther Frisch is the biological father to, since finding out would involve extensive DNA-testing. Through research for their documentary, DR knows of 15 children from Denmark, Sweden, Finland and Germany who share the same father.