It seems our culture is heavily decomposed into two groups; the god-fearing idiots, who use the bible and conservatism to justify most moral assertions –
and the super-liberal hippy / emo / hipsters, who feed off of Margaret Mead’s assumption-driven dogma and like to say that “sex is just sex” and it’s only repression that can be damaging, not sex itself.
The simple fact of the matter is that the sex drive, like everything else about humanity, evolved. It evolved in complicated ways, but due to simple evolutionary pressures.
A woman carries a child, puts a 9-month energy investment into it. Doing this at all is a substantial danger to the mother’s life in an evolutionary environment. Thus, being pregnant and giving birth and raising a child with a mate carries substantial reproductive rewards to the mother.
This isn’t always the case for the father, who has an evolutionary pressure to spread his seed at least a fair amount before (and maybe during) any “settling down” happens to occur.
This results in a clear conflict of interest – on average – between male and female sex drives. This is observable in each and every culture – women being relatively reticent about sex, and men being relatively indiscriminate. It is also easy to see how this leads to a large potential for the build-up of emotion. This is already obvious on the woman’s side - if emotions are an evolutionary shortcut to efficient action, then a woman should have emotions that drive her to obtain and secure a reasonably long-term mate. Of course, this means that there will be the potential for significant pain should the woman’s desires be thwarted.
It goes both ways too. If a man is going to sacrifice his “seed-spreading” potential in return for increased likelihood of the children he raises having kids of their own, he’s damn well going to want to know that they’re really his kids. Not an issue for the woman, of course, but absolutely one for the man. The man should have significant pressure driving him to be sure that he isn’t wasting literally years of reproductive ability caring for some other jerk’s kid. Of course this implies that a cuckolded man will have a high likelihood of emotional pain.
If we can agree that what is bad is essentially hurting other people, and that the more good and less hurt caused, the better, then it’s pretty obvious that sex carries more potential danger than most other normal human activities. How about causal sex between strangers? Anyone who’s had causal sex and who is a good observer of humans can tell you two things: one, that causal sex can be done with minimal risk to emotions, and two, that this can’t happen nearly as often as most people would like you to believe, especially for women. It isn’t too hard to take reasonable precautions – but most people don’t, because they like to act selfishly, and to take reasonable precautions and thus to act responsibly would nullify the majority of options these individuals have for casual sex. What use morality when it’s inconvenient, after all?
Even if you like casual sex but restrict yourself to doing it only when you have a reasonable and high degree of confidence that you aren’t hurting the other person, there’s another risk, also quite potent, and equally poo-pooed by all the selfish / liberal nutjobs. Causal sex forces habits in people, and different habits in different people. The habit of causal sex is very strongly correlated to low self-esteem and destructive behavior in women. The evolutionary reasons for this are completely obvious - females are much more likely to resort to casual sex if they can’t get a real, long-term mate. And this must necessarily be accompanied by a lowering of standards, and a lowering of self-esteem, since any airs of “I’m too good for you” will no longer be productive. They’re no longer women; they’re whores.
Meanwhile, the men who engage in causal sex habituate themselves to a lifestyle in which they can spread their seed in substance. If there is any evolved subconscious scale that weighs whether or not causal sex is more in your best interests than a relationship – and there is every reason to believe such a “scale” exists – then the more casual sex a man has, the more that scale will think “why enter into monogamy when I can spread my seed so much more efficiently this way?” History is full of amusing examples of men who are popular and desirable, and can’t hold a relationship together, as they’re always chasing the next thing – and other men who hold together fantastic relationships, and who, interestingly, probably wouldn’t have many options if they weren’t ensconced in marriage already. And how many of us DON’T know a guy who was cheated on, and then becomes highly promiscuous for the next few years? Or the girl who was cheated on and develops terrible self-esteem and insecurities that persist over a few more years? Casual sex usually doesn’t have the same impact that infidelity does, but I feel guilty thinking about the girls with whom I’ve had casual encounters where, in retrospect, those were clearly not in her best interest. It’s true that she gave consent - but that by no means rids me of my moral obligation, even though I acted as if it did at the time.
Certainly there are plenty of contrary historical examples as well, but the supporting examples are so much more ridiculously numerous than the contrary ones that it is unreasonable to deny the existence of a link. Many popular observations about men and women are completely in accordance with these mechanisms; Ladder Theory, a girl bringing along the ugly friend, a guy ignoring or teasing the girl he likes, Pick-Up Artistry, etc.
I’m by no means one of the religious nutjobs, and I by no means advocate pure monogamy, no sex before marriage, etc. My beliefs are this: most intelligent people today consistently underestimate the potential sex has to profoundly affect an individual, both in the immediate and in the long-term. They think about the matter culturally, not practically or observationally. Culturally, as long as someone consents, it’s ok, and you’ve satisfied your obligations. Practically, morally, that isn’t the case at all. When having sex with someone, there is a high average potential for hurt in the short-term and engendering damaging behavioral patterns in the longer-term. You can’t be scared of sex before you have it, of course – but you should absolutely be considerate enough not to jump into it until you have a good idea of whether or not you’re fucking up (heh) the other person thereby. And in whether or not you’re fucking up yourself.