So... you are saying men are like sperm and women are like the reproductive tract... that puts some very strange pictures in my head. Otherwise this is very old news to me.

sigh Here's an idea; give me the grants for these scientific studies and I'll just tell you obvious stuff like this every so often. Much more efficient.

Never trust anything that bleeds for 5 days and doesn't die.

For once Helium is right, individual sperm potency has nothing to do with survival of the most fit.

Depends. There's selection against having lazy/bad sperm. You can have many good qualities, but if your sperm is useless, you are not the most fit.
It's semantics, I know.

Monogamy has nothing to do with it.
Even if you're monogamous, you're still likely to produce less offspring than another man with better sperm, assuming the women are equally fertile. Your male descendants will have a higher chance of inheriting your bad sperm (assuming the bad quality has to do with genes, which isn't necessary), which reduces their chance of offspring as well. It's just a matter of statistics.

Of course assuming all women are equally fertile is incorrect, but it's still true that given the same chances (or hypothetically the same woman), you produce less children than your competition.

In many species, especially in mammals, when females are in heat, they mate with several males. The one that gets there first and the one whose sperm is fittest has most chance of impregnating the female. I think homo sapiens is one of those species, although in modern civilisation things are a little different...

Oh rigth, it makes sense...

Not quite "first" or "last" with humans. It's rather a "window of opportunity", which lasts quite a few days (something like 1 to 2 weeks IIRC), and pretty much anyone who gets to hit that window has a chance. If you're late, fast agile sperm is an advantage, while early in the window, slower (but more resistant) sperms would be better.
While human females don't mate with different males on the same day that frequently, different candidates within the same "window" are definitely possible. Nothing to do with civilization BTW. The only civilized thing that messes with evolution is birth control.

hey dose this make you think of a nice on-line game some one should make it,
sperms vs the emuns and obstickles protect the egg vs reach egg. who will win who will be the savior out of the sperms than its a race.

hey its a cool idea i thing it will make some loot or even fame.

i think ill my it and copy right it. think out side of the box young one.

That's a rhetorical question...