If we have evolved as beings to crave for, and therefore benefit from, close and long term relationships, then why does the phenomena of rape exist in nearly all known societies?

The answer may at first seem obvious. It is in a male's interest to impregnate as many females as possible - whether he is in a close relationship with another female or not. If a female does not want that male (ie she perceives him to be less attractive than other males which may be available) then he may take the opportunity to force sex (and hopefully pregnancy) onto the female. The situation however is not this simple.

Why would women not either abort, or simply not get pregnant after suffering the trauma of rape? Indeed pregnancy, or the risk of it is something which makes rape even more traumatic for the victim. There is already a biological mechanism to enable this (spontaneous abortion). Why isn't it triggered? It is such a simple thing - if it is in the interests of the woman, why has it not evolved?

The answer is that it is in the interests of the female to let the pregnancy go through. The rapist was clearly powerful enough, clever enough or fit enough to carry out the rape, and so is probably carrying very good genes.

The Vikings who raped, pillaged and plundered their way around much of the world were fit, strong, able men, and would have carried excellent genes - probably considerably better than the stunted and inbred specimens in the local villages they ravaged. A Viking man would have given good sons, who would be likely to successfully rape other women, ad infinitum. It would have been far more beneficial for the pregnant rape victim to have the child than to terminate the pregnancy.

In fact human females should try to resist a male who they regard as anything less than very attractive, and even try to fight off a rapist. If however, the rapist passes the test of resistance, and she gets pregnant, then she should probably not terminate the pregnancy. She is likely to have a son who will also have the ability to successfully rape other women, and therefore will have many grand-children, for the same reasons. Even if she has a daughter, the daughter may pass those genes onto her grand-sons, and so on.

The explanation doesn't just stop at Vikings of course. Anyone in power, whether the tribal leader, the local war-lord, aristocrat, priest or whatever had that power for reasons. Some of them are genetic (though this may be arguable in the case of aristocracy or priests). The rape-child would carry half of his genetic characteristics - good looks, nastiness, murderous nature, ability to seduce, ability to lie, or fight, or steal, or whatever. In some societies these would be an advantage - clearly they have worked for the rapist.

Rape, while beneficial to the attacker, does carry certain risks, including revenge from the victim or her friends and family, possible disease and so on. Clearly there is a cost, though the benefits outweigh the costs. If all females were able to cooperate with each other, and abort all children conceived out of rape, then there would be no genetic advantage for males to rape, and so the propensity to do this would eventually die out as the costs outweighed the advantages. This of course never happened for two reasons. Firstly because there was no way for the communication to occur for females to adopt the action, and secondly because even if there were, this would fail. It was it the genes' interest to accept the status quo.

This does not mean that the woman herself wants to be raped - though it does suggest an explanation for "rape fantasies" evident in both sexes. Nature is not designed to be kind to the individuals of the species, but simply to enable the propagation of the genes. The woman can be totally devastated, ostracized, and humiliated by the experience, but if she successfully raises even one child who carries superior genes, then this genetic strategy has succeeded.

The lesson here is not that rape is a good thing, just that the desires of the gene, and the happiness of the individual are not always the same, and are sometimes opposed. Rape involves the initiation of force, and is unacceptable to civilized people.