Dreading a Christmas visit from your partner's parents? Contrary to the stereotype of the hen-pecked husband, the chances are that you are a woman.

In a new study by the University of Cambridge, women complained that their mothers-in-law tended to challenge their competence in domestic situations.

It could explain why the atmosphere in the kitchen on Christmas Day could be cut with a carving knife.

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The women also said their mothers-in-law coddled their sons, and expected them to play handmaid to the darling boy.

All this from women who spent the 1960s and 1970s arguing for equal rights.

Social psychologist Dr Terri Apter presented her findings at the British Psychological Society's conference in London on Monday.

She interviewed 34 mothers- and fathers-in-law and 32 sons- and daughters-in-law for the study.

While only two mother-in-law/son-in-law relationship were hostile, 10 mothers-in-law antagonised their son's wife, and two mothers-in-law said they hated their daughters-in-law.

Wifely duties

Dr Apter found that although many of the mothers-in-law expected their own spouses to pull their weight, the same could not be said of their offspring.

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Stay calm - say it would be "helpful" to be left alone Find tasks - ask her to hang decorations If a problem comes up, stick to it alone

She said: "Even younger women who might have feminist values in other spheres seem to expect their daughters-in-law to be there to help their husbands with traditional duties.

"There is a basic conflict between a wife's desire to be equal to her man, and a mother's need to put her child first."

Dr Apter found sons often reverted into "stone-age" males when mummy came to stay.

One woman complained that when her mother-in-law came to stay, it set her husband's behaviour back 15 years.

Advice for mothers-in-law

Don't take skirmishes personally Consult both parents before buying grandchildrens' presents

Dr Apter said: "She was interfering in the daughter-in-law's long-term attempts to downshift his expectations of domestic service.

"The mother-in-law certainly wants to forge a friendship with the daughter-in-law, and she feels very hurt because her attempts at being friends are rebuffed, and she doesn't quite see what she's doing wrong."

Another lost her temper when her mother-in-law offered to do the ironing.

"The offer of help was a reminder to the daughter-in-law that ironing might be her job," said Dr Apter.

As for her own mother-in-law, Dr Apter said: "I'm sure she would prefer for us to have a much easier relationship than in fact we do have, but she doesn't take little ruffles personally".