In my experience, having a combination of men and women in marketing positions is very good for sales. Goes like this:
Male client a) Feels like he's gotta deal with other men because it's a brotherhood, hang out, smoke cigars, talk about "man" shit kinda thing.
Male client
Got into this business because he is horny as hell and if a woman is gonna take him for drinks and chat him up at a trade show... he's gonna buy SOMETHING.
Female client a) Likes the attention of men and takes well to flattery. Male salesman works well here.
Female client
Is tired of men thinking they own the show. Likes to deal with other women, it's a sisterhood thing.
Hey, in the end, sales is all about psychology. People make deals with other people they connect with.