In an interview with the Independent on Sunday, the Leader of the Commons also condemned the media obsession with "Blair babes" as "awful".
"I think there have been times in my career definitely when I have suffered from it [sexism]," she said. "There's a natural tendency to assume that whatever jobs it is that women are doing are thereby downgraded and less important. Actually that is exactly what has happened to me on a number of occasions."
Mrs Beckett feels there is a trend in the male-dominated world of Westminster to downgrade political jobs given to women. She was recently moved from the Department of Trade and Industry.
Mrs Beckett said she was a "feminist" and regarded the term as a "title of honour." She said the publicity of the so-called "Blair Babes" was "trivialising women", adding: "It is also ... trivialising a chunk of the parliamentary party."
Labour polls show women are turned off by the football-loving tendencies of New Labour. Mrs Beckett said politicians not regarded by the media as "one of the lads" can suffer. "It's a problem for anyone who the lads don't think is one of the lads," she said.
FULL INTERVIEW, PAGE 4