Alright, I think we're all pretty familiar with the idea that females in D&D should receive modifiers to differentiate them from males, usually in a way that makes playing them a pain in the ass.

I'm not going to argue that there are no differences between the sexes in real life, but I would like to point out that for gender modifiers make little sense in a fantasy world. PCs by definition are extraordinary individuals, and to have a female who is as strong as/stronger than her male counterpart seems appropriate in that regard.

Biology might not support it, but this is a world where you can be descended from a dragon, demon, devil, angel, or god; where deities routinely bless their champions with magical powers, and where it is entirely possible to fall into a cauldron full of strength potion as a child. In short, there are so many science defying things floating around in the average D&D campaign that female PCs having great strength really seems like an odd thing to get hung up on.

As for the human population in general, they were likely created by gods instead of arisen through evolution. In real life it seems that humans evolved and developed a bit of sexual dimorphism; a race designed by a maker, on the other hand, would not necessarily have that feature if the creator did not desire it.

So yeah.