How to Tell Biology from Bullshit: Polygyny and Female Choice
Echidne has done a lot of work dissecting what is wrong with Kanazawa & Miller's article from the point of view of what you might call basic logic and knowledge of human society. I'm going to write about why their work (and a lot of so-call "Evolutionary Psychology" in general, which I'll call EvoPsy to distinguish it from actual scientific studies of evolution or psychology) is scientifically bogus.
I am a Real Evolutionary Biologist™ by training (*waves sheepskins*) and a science writer by sometimes trade. I will say as a blanket, dogmatic statement that you shouldn't write about evolution if you don't know biology. If you're going to claim to be an expert in the evolution of human behavior, you'd better show expertise in: evolution in general; the behavior of non-human primates; and anthropology, the study of a variety of human cultures. Kanazawa & Miller fail all these tests.
To start with their most obvious scientific failure: K&M state that humans are naturally polygynous (use a mating system where one male mates with many females). They also talk about a variety of qualities men supposedly look for in a mate: youth, hair color (!), beauty, etc.
These two things are opposites. It is true that biologists expect as a default that a mammal about which we know nothing else will be polygynous, because most mammals apparently are. We also expect that a bird will be monogamous, because most birds apparently are.
But -- we always expect that the males are the pretty ones. And the more polygynous the species, the prettier the males are likely to be. It is the male peacock who has the beautiful, enormous tail; the male deer who has the big spreading antlers.
To use slightly more scientific terminology, sexual selection acts on males, because it is females who do the selecting. Females are the choosers, males are the choosees. If biologists talk about mate choice we are usually talking about female choice, because by the very definition of "male" (="the one with the small sex cell aka sperm") and "female" (="the one with the big sex cell aka egg") the female has more to lose by making a bad choice.
If real biologists see a species where the females show more sighs of sexual selection than males -- brighter colors, more complex display behavior, more elaborate secondary sex characteristics -- our gut reaction is, "wow, polyandry, how unusual." 
So, in nature polygyny means males choose their mates *less* and females are less beautiful. In nature, if a male gets to have many mates, he does not get to choose them, they are choosing him. In crude human terms, you can get a lot of action or you can be picky, you cannot have both. Females, who are expected to be more picky, can get mates more easily than males, and so they have the power of choice.
K&M are clearly not writing about "human nature" in the biological sense, they are writing a fantasy of power and sex. Any feminist can tell that they're doing this from their title -- "politically incorrect" is usually shorthand for "I have the power to not treat other people decently". K&M want the power to have sex with many women, but they also want the power to get women to look and act a certain way. This is not nature, this is a fantasy -- something in the human mind.
I'm not denying that the system K&M yearn for, polygyny with male choice, doesn't happen in many human societies. But it is patently unnatural, even anti-natural: it's not the human instance of a widespread natural pattern, it's something peculiar to human societies, something that makes it seem "natural" to behave in ways no other creature does. K&M don't seem interested in learning what that might be, and that makes them even worse scientists than they seemed already.
Because echidne asked so very nicely -- hardly any rains of amphibians or reptiles! really! -- I shall try to make this a series. Not on K&M, because they are too stupid and hurt my brain. But please make suggestions about topics you'd like to see a feminist Real Evolutionary Biologist address. Also, tell me where I need to put in links. Most of this stuff I know off the top of my head, so it's sometimes hard for me to recognize that you won't necessarily take my unsupported word for it.
 Should I put in a picture for illustration here?
 The link here is reasonably scientific, but out-of-date: it's now clear that there are various types of cooperative polyandry even in mammals. Examples: The small New-World monkeys marmosets and tamarins; the naked mole rat, the only fully eusocial mammal; the spotted hyena. Should I put links to accounts of these species?