Married men who do a lot of traditionally female chores, such as cooking and cleaning, have less sex than those who avoid these kinds of jobs, a new study suggests.

However, men who do a lot of traditionally masculine work, such as gardening and car maintenance, have more sex.

"Our findings suggest the importance of socialised gender roles for sexual frequency in heterosexual marriage," scientists from the Juan March Institute in Madrid said.

They analysed data from a national survey of families in the US. Both men and women reported having sex an average of five times in the prior month.

However, the study found that couples in households where chores were more associated with traditional gender roles had more sex than those in which the men did more traditionally female jobs.

The scientists investigated whether couples with more traditional roles had more sex because the husbands were more sexually coercive. However, this did not appear to be the case.

"Wives' reported satisfaction with their sex life has the same relationship to men's participation in household labour as sexual frequency. Had satisfaction with sex been low, but frequency high, it might have suggested coercion. However, we didn't find that," they said.

Furthermore, other issues, such as levels of happiness and religion, did not appear to affect the couples' sex lives either.

"The importance of gender has declined over time, but it continues to exert a strong influence over individual behaviours, including sexual frequency within marriage," the scientists said.

However, they emphasised that the findings should not be used by men to get out of doing chores.

"Men who refuse to help around the house could increase conflict in their marriage and lower their wives' marital satisfaction. Earlier research has found that women's marital satisfaction is indeed linked to men's participation in overall household labour, which encompasses tasks traditionally done by both men and women," they said.

Details of these findings are published in the journal, American Sociological Review.