Men tend to be slightly larger than women, this is because we are omnivorous and have to travel frequently in order to obtain food, as opposed to Gorillas which can sit in one spot for long periods of time with a single male (twice as large as females) and a harem of females. While it might be nice to have a harem, unfortunately it sucks for the chicks, because without competition the Male gorilla has a 2 inch penis and produces very little sperm.
That is another difference...men have much smaller gonads than women, although this is true across all species (by definition).
Another difference is that women have to bear a parasite for 9 months while pregnant, requiring much greater cost to reproduce than for a male...this causes women to be choosier than men. In a recent study, confederates asked random opposite sex participants in a city one of three questions. The first was, would you go on a date with me? Men and women replied about equally with 50% saying yes. The second was, would you like to come up to my apartment? Men answered at about 70% yes, and women answered at around 20% yes. The third question was, will you have sex with me? 80% of men said yes, 0% of women said yes.
These are just some of the amazing differences between women and men.
-Grocat