WatersMoon110
sachiko_sohma
And sex orignally was mainly use for reproduction so the human population wouldn't die off, which is why sex offten results in pregnancy.
Humans have never consciously used sex only for reproduction.
In mammals where sex is only used for reproduction, females come into heat, usually just once a year. However, humans don't ever come into heat. We have (consensual) sex whenever we feel like doing so, usually for pleasure. Sex is probably so pleasurable for reproductive evolutionary reasons, though.
The main benefit from sex the way that humans have it (in my opinion) is the pair bonding, which would have greatly increased the chances of offspring surviving to breed the next generation.
Human reproduction is, rather obviously, intended to slowly keep a stable population. Not to keep a species from dying out. We usually have only one child at a time, and often have children years apart. A species that needed to keep numbers up would have litters. And our children take years of care to be self sufficient, not something seen in species that rely on lots of reproduction to keep numbers from dwindling.
In fact, one of the main problem the people are having is overpopulation. Even though we reproduce slowly, there are far too many humans (due to the lack of predators or most other forms of natural population control seen in nature).
Anyway, that was wildly offtopic.
However, it is idiotic to deny that sex causes pregnancy. And since pregnancy is the only tangible thing sex provides (Yes, pleasure, but we all know that pleasure isn't what it's for. The same way eating is for gaining nutrients, not flavor), we can conclude that sex is for pregnancy.
