What we would expect:
https://www.pnas.org/doi/10.1073/pnas.1414784111Hormonal contraceptives (HCs) are believed to suppress biological processes associated with women’s preferences for cues of partner genetic fitness, cues that may be summarized by men’s facial attractiveness.
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there is some evidence that HC use weakens the hormonal processes that partially account for these preferences ( (for exceptions, see refs. 9 and 10). Specifically, a few studies demonstrate that women using HCs show weaker cyclical shifts in preferences for cues of genetic fitness than do nonusers (11–14). Further, a few additional studies demonstrate that women using HCs demonstrate weaker overall preferences for cues of genetic fitness than do nonusers (15, 16). In one study, for example, women showed a weaker preference for facial masculinity when using HCs versus not (16).
In other words, HCs artificially mimics low fertility (duh!). Recall earlier research:
https://www.medicalnewstoday.com/articles/272697Of course, HCs cannot improve the gene pool, as while women on HCs may choose less masculine men, they will as a direct consequence of taking the HCs not be reproducing with these less masculine men, thereby rendering their improved choices inconsequential.
The only way to improve the gene pool is to identify the fraction of women who most strongly prefer masculine men, and prevent those women from reproducing first. In order that this identification be accurate, HCs must not be present to distort preferences.