sizemilk: "have the potential for a hugely extended, even an eternal life span . . . ie; it's biologically possible."
Some scientists (usually only scientific journalists that have no clue what they're talking about and some scientists speaking outside their field) have this theory, the same ones the WTBTS likes to quote frequently.
Most other scientists that actually study the biochemistry are not so sure (they won't rule it out) since the problem is that when you start messing around with the telomerase levels you start inducing cancerous growths as well. IMHO nature has a way of limiting life for good reason (overpopulation being one of them). There may be ways to extend life but near the end the nuclear-level of our cells will start breaking down, the sun will eventually die and the universe will reach it's thermodynamic equilibrium. Either way, we're going to be dead.