I finally saw this film for the first time last night after hearing how wonderful it was time and time again.  I have to say that the reviews for this film are right.  It's very smart and excellently paced, keeping your attention and testing your wits.  Vincent Freeman was born into the world conceived in love.  His parents had opted to have a child naturally rather than have a child according to new procedures.  You see natural selection is the way to go, having your sperm and eggs inspected as to the perfect child, wiping out all disease and medical problems, mood disorders or any chance of early death.  These genetically altered children are considered 'valids'.  Vincent was born an 'in-valid', not expected to live more than 30 years.  Because of this set-back Vincent will never be allowed to realize his dream of space travel for only 'valids' are allowed to enter the training program.  You must be of the utmost physical shape.