It's not just CAS, it's the entire game.
When I start a new game I watch the game mass-produce female Sims as soon as my new household moves in. The game immediately starts sending adult premade Sims to my neighborhood to loiter, jog, or go fishing. Soon after that, the game starts generating female aliens, mail carriers, pizza delivery NPCs as well as an elder female gardener when there's a community garden nearby. Then it starts generating single mom families so their kids can populate playgrounds and parks.
I delete NPCs until I get what I think is an appropriate mix of genders and age groups. Last night I deleted 7 female pizza delivery NPCs before the game finally generated a male. This happens in most of my new saves so I don't think that it's a coincidence. Then I noticed that the game had generated 6 female Aliens so I deleted 5 of them. I deleted 3 more after that before the game finally generated a male Alien.
Maybe this happens in my saves because my playable Sims are almost always male but I don't think so.
Right now I'm looking at the traits of all of the premade Sims to see how Maxis has doled out traits since the base game because it seems to me that a disproportionate number of females are creative based on which ones I see ad Infinitum any place there are easels or music instruments.
PS: I'm a female gamer who has played many different types of games for a long time. TS1 and TS2 were never this bad in terms of gender disparity not just in CAS but in the whole game. It goes a little further than the disparaging remark made about hand tools.