Yes, I'm kidding and no, I am not about to say that one gender has a lower IQ than the other. But imagine a manager who has worked with men and women, studied gender differences and brain functions and came to the scientific conclusion that women and men are less suitable for specific jobs and that preferring one gender over another for certain responsibilities is therefore not unfair discrimination. Whether this conclusion is right or wrong, it's only an opinion with the same logic, scientific backing and fallibility as the policy of assigning responsiblity based on IQ. Who are you to tell him how to run his business?
Imagine two managers: One has the opinion that women are better at team-work, handling customers and departmental communications and therefore prefers to hire women, the other thinks that women are prone to emotionalism, PMS and pregnancies and therefore prefers to hire men. The former would be praised, while the latter vilified and sued even though both are exercising the exact same decision-making right and ability.
Or what about personal issues? What if a man simply doesn't get along with women? What if a man decided that gender differences too often cause friction between mixed co-workers? What about all the female HR managers who don't hire women for personal reasons? It's quite common in my experience for women to object to other female workers and to prefer working with men.
There may also be religious reasons: I know of a company run by religious Jews that exclusively hires women (over 100 women, no men). Both the men and women in these circles support this policy because it serves their purposes and allows for a much more comfortable work environment.
Perhaps you think it's unfair that some companies hire more men than women and vice versa, but then why isn't there affirmative action on companies that only hire people with a certain level of IQ, experience or personality? There are plenty of practical and valid reasons for hiring one gender over another whether you agree with them or not. What is the difference between discriminating against someone based on their natural intelligence or charm, and hiring someone based on their natural gender-based differences?
The common argument is that Affirmative Action is a correctional policy that aims to balance a historical imbalance. But this would only be valid if the imbalance was due to unfairness, not fact. Feminists may argue that gender differences are only due to oppression, patriarchy, society and upbringing and that discriminating based on gender therefore only reinforces such chauvinism and unfairness, but you'd have to be an idiot not to see at least some inherent general differences in the genders as a whole as well as to ignore all the scientific evidence on brain differences. In any case, such practices effectively eliminate any of the aforementioned opinions or valid reasons for preferring one gender over another.
Most people complain that Affirmative Action is unfair, that it creates a privileged caste, or forces businesses to hire less qualified employees. But isn't there an even more basic issue? One would think that, at the very least, a country that values its freedom would protest against such censorship and Marxist/Socialist government practices.