The head of a Dutch fertility clinic has been accused of using his own sperm instead of that of chosen donors to father dozens of children.

Twenty-three parents and children of those born through IVF treatment from the Bijdorp medical centre, near Rotterdam, have gone to court to ask for tests on the DNA of Jan Karbaat, who died aged 89 last month.

Karbaat ran one of the country’s largest sperm banks in the 1980s and 1990s, billed himself as “a pioneer in the field of fertilisation”.

But reports began to emerge last year that suggested he may have been fathering the children he helped to conceive - in a plot twist that has echoes of Glasgow crime drama Taggart.

Women who used the clinic report being told by Karbaat that he was getting “fresh seed” from a room next to the insemination area, and say they have noticed physical similarities between Karbaat and their children, including eye colour, that don't match with their official donor's characteristics.

Karbaat reportedly admitted to having fathered about 60 children in his time at the clinic, which closed in 2009 amid reports of irregularities, and requested in his will that no DNA tests be carried out on him post-mortem.