I love a good N count controversy, and this seems guaranteed to deliver ...

Great write up here

Intro:

New research published in the journal Psychological Science reveals a pervasive but unfounded stereotype: that women (but not men) who engage in casual sex have low self-esteem. This finding was consistent across six separate experiments with nearly 1,500 total participants.

Conclusion from the study itself

Finally, the stereotype appears to be unfounded; across experiments, the same participants’ sexual behavior was not significantly correlated with their self-esteem.