>>OK, then, where did the 2nd generation come from? How does the genealogy go after the moment when there are three people on Earth - Eve, Adam and Cain?
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>Oh yeah - now I remember going through this with you...don't want to go through all THAT again. Suffice it to say, you can look here if you really want to know: http://www.answersingenesis.org/home/area/tools/cains_wife.asp (please read it all)

In SF, solving the continuity flaws in the story with time travel is considered a, pardon the pun, deus-ex-machina solution, a duck tape. This idea that between G 4:8 and 4:17 there's about a century... is completely unnecessary. For those who believe, it doesn't really have to make sense - they'll believe it anyway. For those who don't, it doesn't matter, because the rest also doesn't make much sense either, so why bother?

But, in the "please read it all", why does the space between the question and the "the period from Cain’s birth to Abel’s death may have been 100 years or more" have to be stuffed with the straw man argument (involving a fictional character from Sagan's book)(besides, why is dr Sagan mentioned as just atheist, not as a scientist, writer etc? show some respect, guys, remember the golden rule you claim to have invented)(oh but he's dead, so "de mortuis nihil nisi bene", being atheist is the one good thing you had to say about him), why all the bragging that "skeptics then make the logically fallacious jump" (now why do you need logic if you believe?), why "Sagan cleverly used common questions" - is it better to be stupid, maybe?, why the whole mention of allegedly original sin, and all the text between "God did not start by making a whole group of men" and "Cain's brothers and sisters"? So because you can say to yourself you made me read it? Well, I read it, and while it may have had an honest intent to answer the question the best way, it also managed to irk me vastly, by using the arsenal of the low end propaganda. It's not coming across even as a honest attempt because of it, it looks rather like "I'll answer your question, but first let me slam a few slanders against the likes of you".

>Maybe a good question for you would be...if we evolved from a single celled organism, how is it that the male and female versions evolved at the same time - given their extreme differences? And, if they did not evolve at the same time (meaning one was not required early on,) why did we evolve differently at all?

Does evolution answer any "why"? It just works the way it does. And let's not forget that many unipolar species are wildly successful - sponges are still out there, right? And they may outlast us.

As I see it (and biology is not my forte - these guys were in the other, newer building, we were stuck with the physicists in the old one), the differentiation between the genders went as far as it increased the chances of successful procreation. Whatever worked in the long run, came to stay - or vanish.

Now if the question was "why evolve male/female pairs at the same time" - since their main biological function was to match each other, actually the only thing that's the difference, evolutional change which would change one mate beyond compatibility with the other mate would not be impossible, but wouldn't it end nowhere? Just imagine mismatched genitals - how would they mate? How would these be passed to offspring? I think they simply had to evolve symmetrically or at least compatibly, or they wouldn't mate.