Where were you in 5th grade when they explained this stuff?
No, seriously, men and women are different. That does NOT make one sex 'better' than the other, as some of the above posts have indicated. Not at all.
Difference can be wonderful. I like the way things are set up, with two different sexes. It adds a lot of the flavor in life.
Men and women are different. It's always been that way. Not just physically, but in other ways as well. And the physical differences are never 'just' that. What kind of difference is there between someone who has the capability to bear life and someone who doesn't? That's big.
Men and women can be different without being unequal. An apology to all math majors out there, but it's true. It's apples and oranges. An individual person could be said to be better than another individual, but you can't generalize that statement to such a degree as to encompass the whole human race.
Men and women are human; we share many traits. But in some very important ways we are different, and the difference is beautiful. I could not imagine a world without it.