Elizabeth Truss calls on parties to widen selection of candidates, with one in 12 MPs related to current or former politician

A Tory education minister has criticised the number of MPs who come from political families and urged all parties to widen their selection of candidates "beyond the usual suspects".

Elizabeth Truss, who is considered a Conservative rising star, said attacks on the number of old Etonians at the top of government could be broadened out to apply to the number of children of MPs becoming MPs.

Nearly one in 12 MPs is related to a current or former politician, according to figures published by the House of Commons library. As well as six married couples, there are siblings such as Angela and Maria Eagle, two Labour frontbenchers, and the children of former MPs, such as Ben Gummer, son of Lord Deben, formerly John Gummer, and the shadow communities secretary Hilary Benn, son of the late Labour leftwinger Tony Benn.

David Cameron's great-grandfather was Sir William Mount, a Conservative MP, while Nicholas Soames, a Tory backbencher, is the grandson of Sir Winston Churchill.

Truss particularly singled out the "red princes", a name given to the children of some Labour senior figures with political ambitions – although this applies to only two standing in 2015 so far: Will Straw, son of the former home secretary Jack Straw, and Stephen Kinnock, son of the former leader Lord Kinnock.

Truss told BBC Radio 5 Live: "I think it applies across all of the parties actually … What we're seeing is children of MPs becoming MPs. There are some brilliant children of MPs who are MPs, like my colleague Ben Gummer, but what I do want us to see is a more open politics.

"It's not just about public school boys or girls, it's actually about people coming from the same family, people who have always been involved in politics being involved in politics. I think it's about broadening it out beyond the usual suspects. If you look at the Labour team we've got a husband and wife in the top team, we've got brothers in the Labour party as well. What we want to do is enable everybody to aspire to be part of the political system."

Last weekend Michael Gove, the education secretary, attacked the "preposterous" number of Etonians in the prime minister's inner circle, arguing that such a bastion of privilege did not exist in any other rich country.

Lady Warsi, a Foreign Office minister and former chairman of the Conservative party, backed Gove's comments and appeared on ITV's Agenda programme with a spoof newspaper implying she would like see a headline saying: "Number 10 takes Eton Mess off the agenda".