In a London Weekend Television programme, Westminster Women, Jane Griffiths, the new Labour MP for Reading East, says that two Conservative MPs in particular make sexist gestures to put women MPs off their stride as they speak.
"There are things that you half hear and you're not sure if you heard it right," she says, "and they use gestures and body language which gets missed by the cameras so they can't be caught at it.
"They do it on purpose. It's to put us off our stride. It's just another tactic in the battle and they will use anything, and men have always done that, when they feel threatened by women."
Asked about the gestures used, she cited the one "where they put their hands out in front of them, as if they are weighing melons. There are two Tory MPs who do it on a regular basis. I don't know who they are because they all look the same to me."
Underlining the Tory backbench obsession with breasts, Clare Short, Secretary of State for International Development, said the men would "giggle" when cervical cancer or other things to do with women's health were raised
"It was very public schoolboy," she said. "Breasts, of course, just finished them off completely."
Last night, Ms Griffiths told The Independent: "Frank Dobson made a statement in the House today about the National Health Service, and when he talked about breast cancer, whenever he said the word `breast' ... they were trying not to, actually, they were trying not to giggle or smirk, but they were doing it. They couldn't help themselves.
"And they seem to be the younger ones, rather than the older ones, who are more dignified."
As for the MPs pretending to weigh melons, she said: "I've seen this several times. More than once I've caught sight of it out of the corner of my eye. Then you turn and you just catch them stopping doing it.
"Chaps on building sites will shout things out, but, I mean, most of them are honest about it because they're not pretending to be serious.
"But these people are supposed to be part of our political debate, and this is their idea of the level at which it should be.
"Frank Dobson had a question about pregnancy care today, and his answer was, `Well, we do have figures and we know approximately how many women in a given area are likely to give birth within the next 12 months ...'
"That was thought to be tremendously funny by the Tories, who thought it was a big hoot."