"How many professional footballers have had their sons become professional footballers?" asks Henry Read. "Has a father and son every played at a professional level together, either in the same team, against each other or neither."
Darren Ferguson, Shaun Wright-Phillips, Neil Mellor, Paul Dalglish, Nigel Clough, Frank Lampard Jr, Jamie Redknapp, Michael Owen, Paolo Maldini, Michael and Brian Laudrup, Jordi Cruyff ... the list of sons whose fathers were well known professionals just goes on and on and on.
However, special mention must go to the Summerbee clan who, as Thomas Robson points out, boast not two but three generations of pro footballers in the family ranks: journeyman grandfather George, superstar son Mike and rejected-by-Sunderland grandson Nicky. Indeed, so impressed was author Colin Shindler with one of Maine Road's favourite family's achievements that he felt compelled to write a best-seller about them, entitled Fathers, Sons And Football.
However, it was the second part of Henry's question about father-son combos playing together that prompted the most interesting response.
Many of you pointed out that Eidur Gudjohnsen replaced his father Arnor, a fellow striker, during Iceland's game against Estonia in 1996. Alas, the Gudjohnsen's never quite made it into the on-field XI at the same time. According to Lindberg Simon, they were both supposed to start in the following international but Eidur broke his ankle and was unavailable for selection.
Meanwhile in Finland, writes Antti Lassila, one recent father-son duo to play in the same team are "the Russian-born Aleksei Jeremenkos of HJK Helsinki, who played regularly together during the last Finnish season."
Quite a few people also name-checked Alec Herd and his son David, who played together for Stockport County in the 1950s, although Kalyan Bose thinks Herd the Younger may not have been a professional at the time, but an amateur or apprentice. Hats off, Kalyan - that's the kind of pedantry we love here at The Knowledge.
As if that wasn't enough, Mike Price rowed in with the George Easthams, who lined up for Ards in Northern Ireland, as well as player-manager Ian Bowyer and his son (no, not him), who played together for Hereford United in the early 1990s.
Finally, our many thanks to all of you who pointed out the Leeds United/Rep of Ireland bloodline double-act of Gary Kelly and his nephew Ian Harte which, while it has nothing whatsoever to do with the actual question, is essential trivia for the table quiz competitor about town.
