Hmm. Thanks to MerricB's page, I went back and looked at the first three sets (which have complete galleries available).
Females in Harbinger:
- Ember (uncommon)
- Arcane Archer (rare)
- Axe Sister (uncommon)
- Elf Archer (common, looks a bit androgynous, but that's elves for ya)
- Lidda (uncommon)
- Vadania (rare)
- Wood Elf Skirmisher (uncommon)
- Drow Cleric of Lolth (rare)
Females in Dragoneye
- Bladesinger (rare)
- Copper Samurai (uncommon)
- Cleric of Nerull (uncommon)
- Thayan Knight (rare; I think this is a female, but I'm not 100% positive)
- Drow Wizard (uncommon)
Females in Archfiends
- Healer (uncommon)
- Mialee (uncommon)
- Champion of Elistraee (rare)
- Evermeet Wizard (uncommon)
- Ragnara (uncommon)
- Dark Moon Monk (uncommon)
- Drow Sergeant (uncommon)
All of those, in theory, are usable as PCs (though, admittedly, there's 4 drow in there). In addition, there's a few females who probably don't make good PCs:
- Tiefling Captain (Harbinger, uncommon)
- Catfolk (Archfiends, common)
- Githyanki Fighter (Archfiends, uncommon)
- Yuan-Ti Pureblood (Archfiends, uncommon)
- Aspect of Lolth (Archfiends, rare)
So, drow and weirdos aside, there were something like 16 female minis, usable as PCs, in the first three sets. True, only one was common...but an awful lot of the commons aren't appropriate for PCs (female or male), anyway. I went through those three sets, and tried to classify the Common minis into two groups: (A) usable as PCs, at least in theory (i.e., humanoid, look at least remotely like an adventurer) and (B) look like NPCs (i.e., monsters):
Harbinger: 20 commons, of which 6 are "PCs"
Dragoneye: 16 commons, of which 5 are "PCs"
Archfiends: 16 commons, of which 8 are "PCs"
So, yes, there's more males than females, but "virutally no female minis" overstates the situation.