An MP has claimed some Conservatives make lurid hand gestures towards Labour women during debates in the Commons.
Sarah Champion said there was an "insidious" sexist culture in which "some Tories are very good at gesticulating about female assets".
Ms Champion became a Labour MP a year ago after winning a by-election in Rotherham.
She formerly worked as an arts administrator and chief executive of a children's hospice.
Ms Champion did not rule out the possibility that male Labour MPs also engaged in sexist behaviour in the chamber, but said she had not witnessed it.
The Conservative Party declined to comment.
In an interview with BBC Radio Sheffield, Ms Champion said female MPs from her party were often taunted while speaking in the Commons chamber.
She said: "I think it is utterly appalling. It's deliberately trying to degrade people, it's sexist and people ought to be pulled for it."
Interviewer Rony Robinson asked, for clarity, whether she was saying that "MPs opposite you, you're standing up making a speech about something, and they are using their hands to imitate breasts and bottoms?".
She replied: "Yes".
She said she had not reported the problem to Commons Speaker John Bercow, adding: "You have to pretty much ignore it.
"If you see it and you can catch someone's eye then telling them what you think about them, but then you end up in a slagging match which I don't think is helpful.
"It's so insidious, it's so part of the culture there, it's overlooked rather than ignored I'd say."
Ms Champion is not the first female MP to complain about the behaviour of their male colleagues in the Commons chamber.
In 2004, a study by researchers from Birkbeck College found "shocking" levels of sexist abuse, with male MPs of all parties pretending to juggle imaginary breasts and jeering "melons" as women made Commons speeches.
Some 83 MPs gave their answers in 100 hours of taped interviews for the study "Whose Secretary are You, minister".