The other day my daughter said to me, "Feminism is just fine, but men and women are not the same." She is an aspiring neuropsychologist and given any social situation, where I see the group dynamics she sees a brain chemical.
From a sociological perspective there are a lot of reasons why gender differences exist and a lot of uses to which groups put them. From a marketing (or outreach) perspective what matters are the patterns. Here are a few that I see:
1) Expressed vs. Implied: Marketing to men has to be tangible - auditory, visual, kinetic (hear it, see it, move it) versus to women merely a suggestion is enough and even preferable. Another way of putting this is that women are engaged with the story around a product while men are engaged with the idea that the product itself approaches perfection.
2) Status: Men buy things to compete with other men and they think of it as "acquiring," so there is a certain level of permanency. Women will buy virtually anything if they think it makes them look good. For women, the competition is self-oriented - between themselves as they imagine they are, versus as they imagine they once were or could be.
3) Delegation: If men could get away with never setting foot inside most retail environments they would, because they see shopping as feminine. So they prefer either to automate the process (e.g. shopping online) or to let the women take care of it. Versus women see shopping as a "quest" for the right thing which hopefully ends in a "Victory."
4) Time: For women, shopping is a destination, an activity, a hobby, and a release and so they lose all concept of time once they enter a store. Versus men believe that time spent shopping is time wasted.
5) Guilt: Both women and men feel guilty about spending money. Both justify the guilt in some way. Women tell themselves they are shopping to take care of someone (even if it's themselves) versus men justify purchases based on whether it enhances their prospects for survival - not just literally but in the abstract sense, e.g. survival at work.
At the end of the day men and women may purchase the same things. Literally - clothing, perfume, even tattoos can be unisex. But the mode of taking in information that drives a purchase, and the motivations for handing over the money, do seem to differ. A very interesting topic of study.