The recombinant embryo is grown in-vitro during the flight to Pandora, which takes 3 years (ship-time/ 5 years Earth time... it's a relativity thing). In that time it reaches near adult size, since the locals mature fast. When it is "born" (or more properly de-canted) as a post-adolescent, it looks like a Na'vi, and can live comfortably on Pandora, but it has enough human neurophysiology to be used as an Avatar, or surrogate body.

The human volunteer then becomes a CONTROLLER. Using PSIONIC LINK technology, the human controller can remotely control the avatar body out in the wilds of Pandora. The controller receives all sensory input, and provides all motor control to the body. Essentially, the controller lives through the avatar, and is completely unaware of his own body while linked. Each avatar is genetically keyed to its respective human controller.

By communicating with the locals through these avatars, which are less alien to them, the RDA has had some success teaching them English and basic skills.

So Tom was going to be one of these controller guys? That's right, they tell him. His embryo has been growing in vitro at the lab for several months. This is significant since only one in a hundred volunteers actually produces a viable composite. Each viable embryo represents an investment of over 20 million dollars.

So they are offering Josh the same contract they gave his brother. Since he is genetically identical, he can step into his brother's shoes, and become a controller. The next mission leaves in three weeks, so he will have to go through a crash training course, but it's still better than wasting a good avatar.

The agents grin like jackals. The pay is great, and it's a chance to be part of the great adventure.

Josh tells them he went for that line about it's not a job, it's an adventure once already, and it cost him the use of his legs. And ten years is too long a stint to sign up for. The army taught him a couple things. He tells them to take a hike.