What would happen? Would he be screwed up and if so how?
We’ll assume he could see pictures of the outside but never actually saw it (not even out a window) for himself.
Oh, forgot to add.
Let’s say he was exposed to the outside for the first time at the age of 18. How would he react?
And another assumption-he could interact with other children who had also never been outside.
I would expect that a person who had been raised indoors might have some hellacious allergies when exposed to grasses and pollen and pollutants and other airborne substances.
Well, you’d have to keep it indoors once you declawed it. 
I too think that his or her immune system may not be quite right and may never adjust to normal. It would take the person a while to get used to varying temperatures and exposure to the sun. I am not sure what would happen after no sun exposure during development. I might take some time to learn soutdoor skills like walking on uneven terrain, swimming, bicycling etc.
They would be really, really white and they would not like outside because there is to much smog and it would smell bad to them.
They would find a place and stay inside as much as possible but as a good side effect would never look any older than about 25 years of age because of low exposure to the sun’s damaging rays.
Well thanks to Playstation 2, this is practicaly the case with my sons.
I remember last summer I suggested they go outside and play. To which they responded with in their most whiney voice: “Nah, it’s too hot outside…”
Too HOT outside? WTF? Appartently they never heard of a water hose. :rolleyes:
My parents problem was getting me to come IN.
Funny how life works.
I think that once they got used to it they would be totally bitter that you had withheld this incredible experience from them. I know I would be.
He will know from TV and the Net what the Outside is supposed to be like. As long as he’s not given some other conditioning, I would assume he could steel himself for the outside and nervously go outside the Caves of Steel. I really doubt that the Outside would send him into Asimovian hissy fits.
I agree, but I think that the kid would also become extremely agoraphobic and would probably never leave the house anyway. People rarely break out of the habits forced on them when they were young; a kid raised indoors would be just like a feral child who can’t live inside, only opposite. IANAChild Psychologist, though.
Hmm…the child’s sleep cycle might end up being “interesting,” as well. I think I remember reading that a human, deprived of any “day” or “night” information, will eventually settle down to a stable sleep-awake cycle of something like 30 hours. (I think I’ll try to find more info. Correct me if I’m wrong.) I don’t know what would happen if you lived your entire life like that, since birth, though.
I also seem to remember that people raised their entire lives in a heavily forested area (like a jungle) can have problems with perceiving distances and depth if they suddenly go to an area where the “horizon” is more than a few hundred feet away, at most.
Might they be sensitive to noise, like in a crowd, or on a busy street?
Perhaps motion sickness, if they tried to go for a ride in a car?
You might see if you can get a grant to buy and orphan and perform this experiment but it’s already been tried on The Simpsons.
Reminds me of a bit from the book of 2001: A Space Odyssey IIRC when Floyd meets the child of one of his colleagues on the moon base, a fined boned and delicate girl who was born on the moon and developed differently than she would have on earth. I don’t remember if it went into more detail but I would imagine that physiological differences would go far beyond small bones. I think it’s safe to say such a person could never return to earth…
I think you would wind up with a child that looks like a Morlock.
But that’s just my $0.02 
From a medical point of view, I think you need some UV light for Vitamin D production which is essential in bone mineralisation…the kid would have rickets and bowed legs. Unless of course you gave adequate supplements.
You might be able to get an inkling of what it would be like by reading about people who are allergic to the sun. I don’t know the name of the disease but I know there is a condition where people basically can’t withstand any real light at all and have to spend their days indoors, although I think they can go outside at night.
Does anyone know what I am talking about?
A few months ago the National Geographic ran an article on the sun and one of the photos was children getting UV theraphy in Siberia or some ungodly northern latitude place that had virtually no winter sun.
Xeroderma pigmentosum or polymorphic light reaction syndrome?
That must be it. It’s not the same as never seeing the outdoors but it might be the closest real life example.
Anyone know if this is the subject of a book? Surely someone has woven a storyline around such a premise…
Part of the plotline of the movie The Others involves children who cannot be exposed to sunlight.