I don't know that you even have to take it back to the baby issue - I'm not sure we know for a fact that even regular Cylons don't age. We haven't seen variation among the 7, true, but we're seeing a relatively brief chunk of time where aging might not be that apparent. Most planet based Cylons would have died in the attacks and been reborn, and who knows what the ship based ones were up to in the time preceding the attack. I'm not saying they do age, at this point, but I don't think we know they don't. So Tigh, who clearly has aged considerably during the time when he has been known continuously by non-Cylon characters may not necessarily require all that much explanation. If someone who's childhood is known by other characters is a Cylon though - Lee, that is - I'd need a lot more to go on.
brenda, I'll try to make my thoughts a little more clear. I agree that with the other 7 Cylons, we have no evidence for or against their aging, and maybe they do, in fact I'm hoping they do. But my main point was that they download after death into fully grown adults of varying ages (maybe Cavill chose an older body so people would take him more seriously?). And maybe that wasn't the original order of things. Maybe the orginal idea was to live a full life, die, and be downloaded into an infant model, kinda like reincarnation with the benefit of remembering your past life and try to do it better. But the 7 got tired of that and just started fastforwarding the process and started dl'ing into fully formed bodies. But the other five disagreed with this cheat, split, were disowned/disowned the 7, and have continued starting from ground zero and living their lives.
Although that doesn't explain the lack of self/cylon-awareness-- unless that's the catch: if they dl into a newborn, they don't conciously retain their life's experience, hence why the other 7 chose to skip the hassle of growing up and loss of info. This attitude could be brought on by a desire to fight, whereas the 5 have no interest in warfare, but in living and in humanity, so they choose life/living/growing up, and not being burdened with past lives brief ambitions and grievances. In this scenario, the Final Five would be on Humanity's side.
And if the Final Five had children, then the half-Cylon soul would be created in the hybrid babies, carrying latent Cylon information and abilities. And maybe the Final Five, cut off from the basestars and the other 7 Cylons and their resurrection ships, lacking new bodies to dl into, found a way to dl into pure human babies with their Cylon souls/minds, and so you get a human child who almost has a split personality or a latent purpose. And as the generations go by, that same Cylon soul/mind downloads into different babies, so "the players change but the roles stay the same"? (I ashamedly admit to misquoting Leoben from Flesh and Blood.
My mind is officially blown.
As much as I'd love to take credit for that, Austin, it's something I gleaned from the TWoP boards.