CLAMP has said though that they wanted Watanuki and Doumeki to be the only male characters because they thought they would be OVERWHELMED by any others and they really wanted them to stand out, especially Watanuki. Plus, Holic runs in a seinen magazine, whose primary readers are male and want to read stories with cute/beautiful "girls" (in quotes because some of the characters in Holic are spirts and thus neither technically XD) in them. Even if a lot of the readers ARE female, there's still the marketing genre to consider, and trust me, I know their editor has considered it and no doubt made suggestions. There isn't a "gender-blind" magazine out there to run things in, especially in Japan, so it's always going to be targeted at one gender or the other. I seriously doubt that CLAMP is sitting around saying "everyone who's female is insane." They're just designing cute girls and fitting them into their plot.