gendered nouns

I have never ever understood the existence of gendered nouns. Seriously. I'm thinking of Spanish here, but I'm pretty sure it happens in all the Romance languages, yes? I know Latin has 'em, so that would make sense. As for other languages, I have no idea. German doesn't have them, am I right? I took a German class in like, third grade, but all I remember from it is how to count to 29, and the word for spaceship (Raumschiff—I think that's how you spell it, anyway). But English is more or less based in German, and English doesn't have them, so it would make sense for German also not to have them, right? Whatever. I'm rambling.

At any rate, what gives? From what I can tell, it's a completely random distinction separating nouns into two separate and completely useless categories (three, if you have neuter nouns—damned Latin and its complicatedness) for no discernible reason whatsoever. Just so they can have more ways to say "the." And where did the "gender" terminology come from? Why can't they just be categories A and B (and C)? Why feminine and masculine (and neuter)? What, pray tell, makes the wall (la pared) more feminine than the floor (el suelo) or an ankle (un tobillo) more masculine than a wrist (una muñeca)?

The way we learned it in Latin class (assuming memory serves, which may be a steep assumption), there are declensions, and first declension nouns are feminine (e.g. silva—forest), second declension nouns are masculine (e.g. amicus—friend) and third declension nouns are neuter (e.g. caelum—sky). I think. But I don't remember if this is always the case, or if it's just generally like that and there are exceptions; I don't know if you can say "first declension" and that automatically means "feminine" and vice versa. I feel like that's not the case, because if it was, why would there be both terms? And now that I think about it, there are more than just three declensions, right? I mean, the "family" words have to go in there somewhere—mater, pater, soror, frater—and they don't go in those three. Yes, yes, I'm remembering now, there are at least five. Possibly more.*

Agh, my kingdom for a Latin book.

And whatever happened to the neuter nouns anyway? Latin's "caelum"—"sky"—is neuter, but it morphed into "el cielo" in Spanish, which is masculine. Why? And the other neuter nouns from Latin that carry over into Spanish, they're not all masculine, are they?** Assuming they're not, how was it decided which ones would be feminine and which ones would be masculine? And what of the nouns that were already masculine or feminine in Latin—did they all keep the same gender, or are there some trannie nouns running around in the modern Romance languages? Do any of the modern Romance languages still have neuter nouns?

And I suppose this depends on the answer to a previous question, but it's on my mind so I'll ask: are the genders consistent across the related modern languages? That is to say, if a noun in two different modern Romance languages has the same Latin root, do the two modern forms necessarily have the same gender? For example, I know the word for "window" in Spanish, "ventana," is feminine, and it is based on the Latin "fenestra," which is also feminine. And I know the word in French is based on the same root—is it "fenetre"? (Well, I know how to say it, even if I can't spell it. So sue me, I've never taken French.) So is that then also feminine? And if so, is that a rule, or only coincidence? And again, what of those poor neuter nouns? Are there nouns that used to be neuter in Latin, and now they're having an identity crisis because they're feminine in one language and masculine in another?

Anyway, I'm veering away from my original question, which remains, why the hell do these categories exist in the first place? Seriously. If anybody can answer me that, I'll bake them a pie. A lovely delicious pie, with a buttery, flaky homemade crust, and fruit filling of their choice (I have a completely unfounded but rather strong prejudice against cream pies).

Anybody?

<sub>*I took two years of Latin, and we used the same book both years, and still didn't manage to get through the whole thing. In fact, I'm fairly sure we skipped over the fourth declension entirely, now that I think about it. So besides all the things I've forgotten in the intervening six years, there were some basic things I never even learned. Not that I'm trying to make excuses; just explaining why I probably don't know what the hell I'm talking about with some most of this stuff.

**The only other one I can remember off the top of my head is "bellum," which means "war," but in Spanish, "war" is "guerra," which doesn't seem to be obviously related, so I don't know if that's a valid example.</sub>

ETA: THIS. I'm not alone!