Allies of Theresa May have questioned Andrea Leadsom's suitability to be prime minister after the Tory leadership candidate appeared to suggest that being a mother gave her an advantage over her childless rival.
Leadsom said she was "disgusted" by the way her comments had been presented and insisted that she believed "everyone has an equal stake in our society", stressing that she did not want the issue of children to be a feature of the campaign.
In an interview with The Times, Leadsom said: "Genuinely I feel that being a mum means you have a very real stake in the future of our country, a tangible stake."
The Home Secretary has previously spoken about how she and husband Philip were affected by being unable to have children.
Business minister Anna Soubry said Leadsom's comments meant she was "not PM material" while Scottish Tory leader Ruth Davidson said there was a "gulf in class" between the two candidates and senior MP Sir Alan Duncan said the energy minister's remarks were "vile".
In a statement outside her constituency home in Northamptonshire, Leadsom said: "I want to make a short statement about the front page of The Times today.
"Over the course of a lengthy interview I was repeatedly asked about my children and I repeatedly made it clear that I did not want this to be a feature of the campaign.
"I am disgusted at the way this has been presented.
"I want to be crystal clear that everyone has an equal stake in our society and the future of our country. That is what I believe and it is what I have always believed.
"I have repeated my instructions to my campaign team that this campaign must at all times be principled and honourable."
A transcript of the interview released by the newspaper following Leadsom's complaints showed the energy minister saying: "I am sure Theresa will be really sad she doesn't have children so I don't want this to be 'Andrea has children, Theresa hasn't' because I think that would be really horrible but genuinely I feel that being a mum means you have a very real stake in the future of our country, a tangible stake.
"She possibly has nieces, nephews, lots of people, but I have children who are going to have children who will directly be a part of what happens next."
The controversy came after the Home Secretary urged her rival to sign a pledge committing to a clean campaign.
In an interview with The Daily Telegraph, May said she likes to keep her "personal life personal" but says that she and her husband "dealt with" the fact they could not have children and "moved on".
"I hope nobody would think that mattered," she said. "I can still empathise, understand people and care about fairness and opportunity."
Foreign Secretary Philip Hammond, attending the Nato summit in Warsaw, dismissed suggestions that politicians needed to be parents to be good prime ministers and pointed to May's depth of experience compared to her rival.
Hammond said: "Theresa May has been clear from the beginning that she wants this to be a clean campaign, fought on the issues, not around personalities but around capabilities and around policies and approach to the future.
"She has signed the clean campaign pledge. I would urge Mrs Leadsom to sign the clean campaign pledge and let's make sure the rest of this campaign is a clean campaign openly fought on the issues.
"I am clear from the people I have spoken to - party members - they don't want to witness a slanging match, they don't want to see any more backstabbing, they want to see a clean debate."
Armed forces minister Penny Mordaunt, a supporter of the energy minister's leadership bid, said The Times report was an attempt to "smear" Leadsom.
She said: "Andrea's first thoughts will be with Theresa in this matter, it's a horrible thing to have happened to both candidates. But we have got to now raise our game and actually give a proper contest to the country."
Mordaunt told BBC Radio 4´s Today programme: "I'm afraid this is an attempt, I think, by a paper that has declared for the other candidate to smear Andrea."