It would be unacceptable if the both deputy leader and leader of the Labour party turned out to be men, Harriet Harman said today.
Harman, who is acting as caretaker leader of the party during its leadership contest, told the Andrew Marr programme the party needed a "balanced leadership".
"I don't think there's a place for all-male leadership teams. A balanced leadership is better.
"We're electing a deputy leader and leader at the same time. I profoundly hope we must have the deputy leader or the leader being a woman."
There is no gender balance rule for the Labour leadership, so Harman's hope of at least one woman in the top team will depend on how members and affiliate members vote in a secret ballot.
The Greens operate a gender-balanced leadership, although this has also proved controversial, with the requirement effectively barring the party from having two women at the top despite having many impressive female candidates for the posts.
Elsewhere in the interview, Harman addressed concerns that Andy Burnham and Yvette Cooper were winning too much support from fellow MPs and starting to close down the opportunities for other candidates to make it onto the short-list, although she stopped short of calling on them to release some of their support.
Under Labour leadership rules, the winner is picked in a secret ballot of members and affiliate members, but to make it onto the short list the candidate needs to win the support of 15% of Labour MPs.
With Cooper and Burnham winning so much support, other candidates are struggling to make it onto the ballot paper and many Westminster observers believe only Liz Kendall will succeed.
"Nominations don't even open until next month but yes, I want there to be a wide range of candidates," Harman said.
"All the people who can vote, I think they want a range of candidates and I'm hoping that's what we will see.
"We do want a wide range of candidates and a very open contest."
She added: "After the scale of our defeat we have to be thinking not only who is the leader but what is the direction we need to be going in.
"We do have to have a big discussion and hopefully that will put us in good stead for a leader to take us through in 2020. You can use the spur of a huge defeat to go back to basics."
Nominations for the Labour leadership open on June 9th with a winner announced at the party conference on September 12th.