Psychological differences between genders as a norm? Yes, that's hard to argue against.
The conclusion that those psychological differences are innate, nearly impossible to overcome, and that the natural order of differences between the sexes is upheld by Just So Stories regarding the origin of the human race? That's much, much easier.
There's a lot of cultural baggage associated with gender. I don't have the links at the moment, but there've been studies involving infants wearing gendered or neutral clothing that measure the reaction from infancy. Regardless of the actual gender, onlookers would compliment the pink-dressed baby's smiles, admire the blue-dressed baby's strong grip, and be confused as to how to react if the gender was neither indicated nor disclosed. From birth, boy-humans and girl-humans are treated differently in measurable ways.
The plural of anecdote is not data, but I also want to say from my own experience that the 'common knowledge' of psychological differences provides a real and effective force towards being a self-fulfilling prophecy. Implicit concepts internalized over the years, such as the norms that girls are dainty and afraid of gross things while boys will be boys and like to play catch, sum to a completely disparate developmental experience. And that's even before the explicit "no gurlz allowed on the internets LOL" messages get added in, or when those who *do* challenge gender norms get subtly or not-so-subtly treated like they're Not Normal and Weird.
Yes, there are tendencies towards physiological differences between the sexes, but psychology is a product of both physiology and socialization. My "major problem" with the evo-psych camp is that it tends to draw the line, with somewhat lacking evidence and justification, closer to nature rather than nurture, and proceeds to argue that this nature is unyielding and unchangable. Saying that the Y or X chromosomes have *no* effect on humans isn't plausible, but ignoring gender socialization differences to suit a gendered status quo is, also, silly.