in theory (my own, science ficiton-like point of view)
長生不老 is possible, imagine there is a "clock" in our body to signal every biological reaction/activities, say, grow up, 性徵 development, 收經﹐ 年老性陽萎﹐ 什致死亡... are control by a clock somewhere in our body. Imagine one day we know how to "recharge" that clock again and again..................
