Mars and Venus

Surprisingly-large genetic differences between men and women: apparently greater than between humankind and chimpanzeekind:

"The important question becomes how men and women actually vary and how much variability there is in females," Carrel said. "We now might have new candidate genes that could explain differences between men and women."

All told, men and women may differ by as much as 2% of their entire genetic inheritance, greater than the hereditary gap between humankind and its closest relative - the chimpanzee.