Don't know about evil, but as much as selfish and self centered. Most women in Western Culture stop at one and two at the most.
Would think the fear of living in poverty is what stops FOLKS having more children. In the past, children were seen as blessings, the more you had the more blessed you are. Of course that does cause conflicts in socio-economics and materialism in the Western Culture, and absentee MOMS with latch key kids, and even worse with divorce, absentee dads when parents can't get along.
1. Evil is a subjective term. You're in no position to say what nature is with any objective certitude.
2. We evolved and continue to survive, so of course we desire to reproduce. Imagine a species that did not have a drive to reproduce. It would have died off literally millions of years ago. So naturally, those species that continue to survive have very productive means of reproduction. We want to reproduce because it's literally programmed into us. It's why puberty happens, hormones exist, and why men like staring at boobs (though I've heard that one might be cultural, not inherently genetic, haven't confirmed though). And natural selection will continue to favor those species that reproduce at a high rate, and get rid of those that don't (like lemmings, whose tendencies were somewhat opposite).
So there's no cultural drive to "keep the species going" but there's a personal drive within each one of us. Have you ever been aroused? Have you ever heard of a female's "biological clock?" That's our bodies wanting to reproduce. Evolution has been exceedingly efficient at programming a voracious sex drive into us. So we don't need to, necessarily, in the strictest sense of the word. But we want to, sometimes very strongly.
Not trying to be rude, but did you think this question through before asking it, or did this explanation really not occur to you?
3. The ruler comment makes no sense at all. Work out the analogy you want to make, and try again.
Religion and popular culture would teach us that killing is bad, so many are against abortion. Some religions go so far as to ban birth control. This is easy to see why as well: just like species, an institution that espouses reproduction will be more likely to survive. Such institutions, usually religions, are powerful memes.
Also, the biological end to sex is reproduction, so that's what the "drive" is rooted in. The female body naturally prepares for being pregnant, etc. We've only recently disseminated and popularized birth control...even a couple generations ago, population control was unheard of and life expectancy was such that you wanted large families to ensure your well-being into old age. For many, the drive isn't just sex but to have children.
For some it's legacy, for others it's a biological urgency to have children, for others it's a (perhaps unknowing) way of looking out for themselves in old age. Hell, females release chemicals into their system that help them "bond" with a baby after birth. Love is also literally programmed into us, just like reproduction. For a few, it really is just about sex. Many of those people will never reproduce.
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However, I suspect you're being very absolute about this. So the answer is: we don't need to. But frankly, if you can't figure out why we end up doing it anyway, there's something wrong.
Biologically, this is what we do; this is what Life does: it deliberately makes more of itself. Sex isn't here solely for fun (ie, orgasm with no responsibility whatsoever). Just a lot of people wish it was.
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Shinier than a speeding bullet.
No. No, it's mostly all that stuff I said earlier. I'm shocked that this is your only commentary on it. Ego is more a psychological buzzword that doesn't hold much water in academic circles, just pop culture.
They do, it's just directed differently. They can't help their sexual orientation, but many adopt because they still want kids.