EDIT: Bah, took too long to type it al out. Curse you, bandaged finger! Curse you!
No, it's just rumored a lot. Fans will cite all kinds of "evidence" but it's mostly conjecture entirely on their part, one instance of a broad copyright (using names that include "Gold" and "Silver"), and a bit of leftover data found in a decompiled version of the game data. There is no evidence to support it beyond "because I think they should!"
Ahem...
First, you have to consider if you can even find any of the older games.
I suppose there are ROMs and emulators that would take care of that, but that's a big no-no here, and I think playing them on the actual hardware is part of the whole experience.
If you can find working carts of them, I'd suggest starting with the second generation, specifically Crystal. It refined the improvements featured in Gold and Silver. It will also be a nice change when you get to the much better GBA graphics and music.
Again, hit up the third version, Emerald, as it adds more than what Ruby and Sapphire had. Most people will say "No, only play Fire Red/Leaf Green!", but they overlook the fact that those are remakes. Playing Emerald will prepare you for playing Fire/Leaf. Fire/Leaf will be almost identical to the originals, but with a fair amount of side-quests that pop up around and after the second to last gym. They are pretty much optional, so you can just ignore them to get the "original" experience.
(Alternatively, you can just go from Fire/Leaf to Crystal, but I find that the change in battle mechanics can be a hurdle to most new players.)
You may want to skip the DS games if you find you're not really getting into any of the above games. It may improve yet again on the whole series, but it's more like a very fancy expansion pack to the GBA games than anything else. Sadly, the creators of Pokémon seem fine with adding only minor changes to the plot and setting, relying more on tweaking the battle system. It's a rather well-done and complex battle system, yes, but that's only half of the whole game.
Ultimately, you should pick the one that sound more appealing to you. If you want simpler battling, go for the GameBoy Color line. If you want more refined battling, go for the GBA games, and then decide if you want to go for the original flavor of Fire Red/Lef Green, or the new taste of Emerald.