According to blogger Erin Polgreen, the answer is yes. Making the case at (of all places) Spencer Ackerman's national-security blog at the progressive website FireDogLake, Polgreen alleges that in books ranging from Superman: Red Son to Wanted to Kick-Ass, Millar portrays even strong female characters like Lois Lane, Wonder Woman and Hit Girl as inveterate second bananas to their books' male protagonists. She also gets some shots in at what she sees as the dubious racial politics at play in Wanted and Kick-Ass, where the ethnicity of various non-white minor characters is played as a punchline.
It's interesting to see an argument against Millar's treatment of "minority" groups (women are, of course, the majority, but you wouldn't know it from comics) hinging on something as comparatively innocuous as his female heroes not proving as heroic as his male ones, given the far more violent and ignominious fates he frequently doles out to his characters. For example, if I were in one of his comics, I'd take out a big fat life insurance policy on any gay and/or black people I knew in-universe the second he came aboard. And with regards to women specifically, you'd think the treatment of rape in books like Wanted and Ultimate Comics Avengers would have at least raised Polgreen's eyebrows, if not her ire. But hey, we report, you decide.