Women who are promiscuous are more likely to keep their reputation intact if they are high earners, according to an academic study.
Attitudes towards promiscuity are heavily influenced by financial independence, while people who disapprove of casual relationships are more likely to know women who are in low-paid jobs or rely on their partner to support them.
Psychologists from Brunel University in London, said the findings may reflect evolutionary behaviour in which men providing for a family feel they need to know that the children are theirs.
The study, Female Economic Dependence and the Morality of Promiscuity, was conducted by a team of researchers on over 5,000 adults in the United States.
The results showed that in US states when women earn more money and are perceived as being economically independent, attitudes towards promiscuity are more relaxed.
They also found that people who know more economically-dependent women tend to be more opposed to promiscuity.
Attitudes were most liberal in Massachusetts, Connecticut, Illinois and Wisconsin, where more women were found to be financially independent.
Promiscuity was least tolerated in southern states, such as Alabama, Utah, New Mexico and Texas.
In two separate surveys, 5,282 American adults were asked questions such as whether women or men should have sex with someone they had just met, and whether women or men who sleep with lots of partners were unworthy of respect or should be judged negatively.
Participants were asked if most women they knew depended on earnings of a male partner, if they were religious and went to church often. They were also asked if their political views were liberal or conservative.
The findings, published in the journal Archives of Sexual Behaviour, showed that women - who comprised just under half of both samples - were more likely to disapprove of promiscuity than men.
Religious conviction and conservative views were the strongest predictors of disapproval of promiscuity among individuals, with a beta coefficient factor, a measurement of correlation, of .26 to .27.
However, knowing many women who depended on men for financial support was also a factor, with a coefficient of .13.
Grouped by state, the link between women's financial dependence and hostility to casual sex was significantly stronger, showing a correlation of .66.
Separate data on women's earnings closely matched the pattern, with liberal attitudes to promiscuity strongest in states with the highest median female income.
Dr Michael Price, deputy head of psychology at Brunel, said the results were linked to evolutionary psychology.
"When women and children depend more on men, it becomes more important for people to know who a child's father is, and promiscuity makes this harder to know," he said.
"In regions where women earn less, people may be more hostile towards practices such as open marriage, and more likely to think that promiscuous people deserve any hardships that befall them."