Central to the question of the origin of life is the polymerization of the first complex molecules that can have catalytic properties and that would eventually carry genetic information. It is widely accepted that our current life form involving DNA carrying the genetic code and RNA producing the proteins that, in turn, catalyze the production of nucleotides, must have been preceded by a simpler life form called the RNA world. The RNA of all terrestrial life forms involves a backbone of dextrorotatory (right-handed) ribose sugars. Theoretically, life could have been equally well based on levorotatory (left-handed) sugars. This so-called homochirality of left-handed amino acids and of right-handed sugars in living cells can be explained as the result of two combined effects, auto-catalytic production of similar nucleotides during their first polymerization events and a competition between left- and right-handed nucleotides.