Tom Watson suggests Labour leader rule change
One of the contenders for Labour's deputy leadership says the party rules might have to be changed to ensure there is at least one woman in the top two party jobs.
Campaigns are under way for both the leader and deputy leader posts.
If both posts are taken by men, Tom Watson said, he would call for a change in the rules for future contests.
The new leader and deputy will be announced ahead of the party's conference in September.
Mr Watson, Labour's former general election co-ordinator, told BBC Radio 5 Live's Pienaar's Politics: "For the first time ever there is a genuine choice of very strong candidates who are women in this election.
"We could end up with two women. But I do think it's an issue that needs addressing if arithmetically we end up with two men - a leader and deputy - and I've said that I'll go back to our National Executive Committee if that's the case to ask them to put them right."
There are "ways you could do it", he said, adding: "You could change the rules so that in future you end up with at least one woman in the leader or deputy role or you could even split the deputy role."
Meanwhile, other candidates for the two posts have been setting out their stalls.
Shadow care minister Liz Kendall, who is bidding to become leader, was challenged over rival candidate Yvette Cooper's criticism of some in the party for "swallowing the Tory manifesto".
The remark was seen as an attack on Ms Kendall, who told the BBC's Andrew Marr Show: "The only thing I've swallowed is the sheer scale of the defeat we faced at the election."
Asked whether she backed David Cameron's plan to remove tax credits from migrant workers as part of his EU renegotiations, she said it was "definitely something we should look at".
But she accused the PM of reducing the EU referendum debate to the subject of immigration.
Shadow leader of the Commons Angela Eagle, who is a contender to become deputy leader, said Labour's election defeat was a "failure of the whole party".
She added: "We have to take collective responsibility for it rather than blaming individuals."