I agree with Peter. A lot of people are happy in their relationships and human beings don't usually think about their genes in future generations being more numerous and successful over other individuals'. This happens in evolution naturally and without living beings needing to be aware of this. We are usually more concerned with morality.
I take your points, too, nesgirl, they are indeed valid and bear some truth. We may not totally see eye to eye but I enjoy our conversations and am quite happy to debate about cloning and a possible asexual solution to many of the problems we have.
A few years ago I heard about a man, a philanderer, who was arrested once it was found that he had fathered about 200 kids and had not supported any of them. They were in their 20s/30s by the time their father was nabbed. None of the mothers had gone off the rails and murdered or harmed their offspring. Sure, some mothers find it overbearing and lose it, but such incidents are not as common as you think. Philanderers can have thousands of progeny everywhere. A few may died before they are old enough to procreate themselves, but, the philandering father will still be ahead of the monogamous male in the battle of the genes. Just thought I'd point that out. Let's also remember that monogamous relationships can go horribly wrong, too, and one of the parents can lose it.[ Post made via Android ]