I'm pretty sure I told you this last year with a chart and everything. To me, it seems that if there is strong appeal to female audience, it will sell better.
And here's the chart:
From like 2 years ago, but pretty legit. More of the titles under "readership that skews the most female" have at some point in their lifetimes sold over 500k (at the time of the chart, I think Haikyuu is the only one that hasn't sold over 500k). Whereas on the "readership skews the most male" side, only Naruto is a 500k+ seller.
Kuroko's ridiculous anime bump from 200k per volume to 600k per volume (over the course of 3 volume releases) is largely due to female audience lol.
Gintama had a whole harem arc, there's definitely enough female characters for a harem. Just that there's a lot of dude characters too I suppose.