Abstract
Biological systems exhibit molecular handedness: During biosynthesis, predominantly L amino acids rather than D amino acids are incorporated into proteins. The origins of this handedness remain puzzling. In his Perspective, Bada discusses results reported by Cronin and Pizzarello in the same issue (p. 951 ) showing a slight excess of L amino acids in a well-known extraterrestrial object, the Murchison meteorite. This finding suggests the existence of an enrichment process in cosmochemical environments and could possibly be the source of molecular handedness on Earth.