You're missing one other piece of the puzzle. An Adam only world would presumably make it hard to create little Adamettes. So what did this god guy have in mind for humans in the long run. Just the one guy, dancing with wolves and stuff, forever? Or was he going to go back to the dirt pile and whip out a few more fellows for kicks? That is, did he intend to populate the planet with more humans at all? And if so, was it with same sex(less?) beings, or did he plan just Adam, forced forever to sing the song "One Is The Loneliest Number"?
If it was just guys, their sin would have been inventing bowling. And beer. But that would have saved god from having to deal with the forbidden tree. Because bowling would have accomplished the same thing, and made for a more believable story.
Anyway, it sounds like procreation was an afterthought. That sex is messy and awkward and involves dissimilar participants (if done biblically correct), means that there was probably no way to make it appealing to anybody. Certain sensual pleasures were probably added even later, once god noticed that just having genitals didn't float A&E's boat, if you know what I mean.
All this because he was in such a great big hurry to get things going. I don't know about you, but anytime I rush while making a universe, I always forget something. Last time I forgot the WD-40 and the damn thing squeaked all the time squeaked all the time. Especially the sex.
So if god didn't simultaneously produce both sexes, methinks his retrofitting explains a lot of things. Since men were not made with women in mind, it pretty much explains the overall attitude of all my ex's. I can no longer blame them for noticing all of my shortcomings. Too, I now realize that "Not tonight honey" turns out to be code for "It was valentines day and all you got me was this lousy rib!"
Whoever wrote that part of the story had probably just had a fight with his shepardess and wanted revenge. At least it is consistent with everything else in genesis. None of it actually explains anything.
Great question. All answers will have to be made up. But then, so was the original story. We can expect no more.
By the way, we haven't addressed "Why children?" here. God makes full-grown adults with presumably incredible maturity (imagine the patience it took to name all the animals). But then he does the Eve thing, sex follows, and out pops these little people unable to care for themselves or understand god's important messages right away. If being obeyed was so frickin' important, you'd think he would have designed some big door so that when birth was about to occur, you just opened it and out would walk a full grown, fully developed, english speaking, semi-competent adult. (Adam and Eve did speak english. They were true Americans and everything. That's a fact.
As a bonus, women wouldn't have to excuse their weight gain.
So kids are a bit confusing too. Why mess up the planet by making little critters that are only cute about half the time? There is no way lions would lay with lambs with a bunch of little brats around.
The more I look at it, the less "intelligent design" appears to be a factor.