His interest in personal history was also reflected in a comprehensive family history research, and he stands behind the website haraldkidde.dk about the Danish author Harald Kidde, which also contains information about his brother the conservative politician Aage Kidde.
Hans interesse for personalhistorie giver sig også udslag i en omfattende slægtshistorisk forskning, og han står bag hjemmesiden haraldkidde.dk om forfatteren Harald Kidde, der også indeholder oplysninger om dennes bror politikeren Aage Kidde.