

They’re not less attractive and they don’t come from bad families if that’s what you were thinking. On several measures they register as having more masculine traits:

We recruited two groups of women who differed in their number of lifetime sex partners in order to investigate several hypotheses related to female sociosexuality. Specifically, we explored whether women who engage in casual sex have low mate value, are especially likely to have come from stressful family environments, or are masculine in other respects besides their interest in casual sex. Women with many partners were not lower than other women on direct or indirect indicators of mate value. Nor were they more likely to recall adverse family environments during childhood. On several measures related to masculinity, women with many sex partners were elevated compared with other women.

Source: “What Distinguishes Women with Unusually High Numbers of Sex Partners?” from the journal “Evolution and Human Behavior”