THIS is why I love the Internet
Does Doctor Who REALLY only have 13 lives????
I heard from a friend that he only has 13 lives. Is this true!?!?!
I though he had an infinite number of lives.
From many episodes of the 1963-1989 series of Doctor Who, it has been made clear that any Time Lord can only regenerate 12 times - i.e. the thirteenth body would be the last. As David Tennant is playing Doctor #10, there should only be three more to come.
HOWEVER...this is sci-fi. There are ways out. In "The Keeper of Traken", the Master (who was the Doctor's arch-enemy for many years) reached the end of his 13th life. He managed to survive by using a highly powerful energy Source to merge with another person's body. He did something similar 15 years later in the 1996 TV movie. Also, Rassilon, the founder of Time Lord society, survived for thousands of years. He achieved immortality, but at the cost of having to hang about in his tomb forever. Omega, his old buddy turned to evil, did something similar by hanging out in a black hole.
So, there are options. Add to all of this the destruction of the Time Lords in the war with the Daleks, plus the fact that thanks to this all the laws previously governing time seem to be falling apart (e.g. see Father's Day), and I'm sure they will find a way to keep him going past his 13th life.