<<Wow, all these posts, and this is the only one that's really an intelligent response. The problem is, although you link premarital sex to a higher probability of a weakened family structure later in life, you can't say for sure that a given individual who has premarital sex will be less qualified as a parent. IF, a certain person could engage in premarital sex, but still be a loving mother/father to all thier children, this would basically negate the argument and make premarital sex NOT an immoral action for this person.>>
In my opinion, a lot of religious teachings make sense even though I am not religious per se.
Yes, I linked it to a higher probability of weakened family structure in the society. These teachings are meant to be applied in general and not specifically to individuals. They are there to promote a healthy society from a group perspective.
Think about lying. Everybody lies but does this mean we should get rid of the notion that lying is bad? If we got rid of the notion that lying is bad, then everybody will lie even more and our society degenorates.
Same with speed limits. When the speed limit was 55, I usually traveled at 65 miles/hour. When it was raised to 65, I now travel at 75 miles per hour. Should we get rid of the speed limit just because no-one seems to follow it? I think that if there was no speed limit, then there would be too many people who will drive too fast.
In the same way, we do not want a society that promotes pre-marital sex as "okay" or "good". Because this society will have too high a level of out-of-wedlock babies (because birth control is not 100% effective) and too many people who have multiple sex partners (how many people actually marry the first person they have sex with?)
I'm not passing judgement on a single person. I'm just saying that as a general rule, premarital sex should not be considered good (or moral if you are a religious person).
<<So, basically, after reading your post, I'm assuming that you think premarital sex is immoral when committed by poeple who lack the responsibility to care for a family, should the need arise.>>
No, I'm just saying that as a general policy, pre-marital sex should not be considered good (moral) because it is bad for society as a whole. I'm not making any judgements on individuals.
<<on another note - when you bring up the issue of animals and certain chemicals: by comparing people to animals in these cases, you include people as part of the animal world. Some animals species mate for life, but many don't. The only evidence we have of these mating practices is by our observation of them. i.e., we know that bald eagles mate for life because we have almost NEVER seen a bald eagle mate with more than 1 other bird, unless it's original mate dies. IF we apply the same reasoning to poeple, we'd not that human beings OFTEN mate with more than one other person in thier lifetime. Based on this information, I dont see how people could be classified as a species that neccesarily mates for life.>>
Well, from the divorce rate, I'm beginning to think that maybe we don't mate for life.

Most animals where the offspring have a long development cycle tend to mate for life -- that's because these offsprings need both set of parents to raise them.
Human offspring have a very long development cycle. Therefore, for the sake of society, we want more couples to "mate for life" or at the very least until their children are grown and leave the nest.
I'm not really saying that humans mate for life but that for the good of society, it's better if we do mate for life. And to increase the probability of humans mating for life, it's a good policy for society to frown upon pre-marital sex.