The purpose of mating for most animals is reproduction and reproduction only, and animals can only reproduce with animals of the opposite sex. There are some animals that have been known to display homosexual behavior. See link and link.
Unless آپ were saying that with humans it's usually the female who attracts the males instead of males attracting females. If that's the case, I think it's تقسیم, الگ کریں pretty evenly. We're all trying to attract each other, regardless of gender.