A man from Rotterdam has begun trying to track down up to 1,000 siblings all over Europe after discovering his father was a ‘super sperm donor’.

Ivo van Halen took a private DNA test after learning five years ago that his biological father donated to three clinics over a period of 20 years. The sperm was supplied to clinics all over Europe.

Van Halen told The Times he managed to contact his father and 42 half-siblings in the Netherlands relatively quickly after taking a DNA test, as many of his relatives had also given samples.

‘Some of the others had known each other before they found out they were related and had almost dated,’ he said. ‘That’s one reason this sort of knowledge is so important.’

But the 34-year-old believes he has hundreds more blood relatives all around the world and hopes to track them down using DNA matching services.

He said he had been surprised to find his natural father’s own father was from Surinam and had African ancestry. He has also used his experience to become a ‘donor detective’, helping people whose fathers were sperm donors identify their relatives.