Angela Rayner has claimed that a newspaper report accusing her of using her legs to distract Boris Johnson was “steeped in classism”.
The Labour deputy leader said she was “crestfallen” that a Tory MP made sexist comments about her to the Mail on Sunday.
And she said it was a thinly-veiled attack on the fact she went to a comprehensive school and had a child when she was young.
According to the paper, Conservative MPs claimed that Rayner had tried to put Boris Johnson “off his stride” in the Commons by crossing and uncrossing her legs.
They accused her of using the ploy from the Sharon Stone film Basic Instinct during their clashes at Prime Minister’s Questions.
In her first interview since the story broke, Rayner told ITV’s Lorraine she felt “crestfallen” by the piece and had to prepare her children for what they might read online.
She added: “I felt really down about that, but I was overwhelmed by people’s response because I just thought ‘Is that what people expect and think about what I do?’”
The senior Labour politician also said the story was “condescending” to the prime minister, adding: “It shows you what his MPs think about his behaviour, but it was also steeped in classism as well, about where I come from, how I grew up and that I must be thick and I must be stupid because I went to a comprehensive school.
“They talk about my background because I had a child when I was young, as if to say I’m promiscuous, that was the insinuation. Which I felt was quite offensive for people from my background.”
She said a wider “cultural shift” was needed, saying: “We have got to teach our sons to be respectful of women and we’ve got to teach our women to be confident about themselves as well.”
Rayner wore a trouser suit for her appearance on the ITV show because she did not want to be “judged for what I wear”.
As the row rumbled on for a third day, a government minister slammed the anonymous Tory MP responsible for briefing the story as “despicable” and “outrageous”.
Armed forces minister James Heappey said: “I just find it outrageous that that colleague who sits within a party that has delivered two female prime ministers, that has two women in the great offices of state, that is surrounded by amazingly capable female MPs on the Conservative benches as well as over on the Labour benches too — I just don’t know what parliament they think they sit in.”
Labour leader Keir Starmer has described the comments as “rank sexism, rank misogyny”.
Johnson himself tweeted that he “deplored” the misogyny that had been directed at her from one of his own MPs.
It is understood the prime minister also contacted Rayner privately by text message to reiterate what he said in his public tweet.