“In 1953 an iconic set of experiments showed that some of the chemical building blocks of life, such as amino acids, could form spontaneously in the atmospheric conditions thought to prevail on the primordial Earth. This gave rise to the idea that the early oceans were a “primordial soup” from which life somehow emerged.
The idea still holds a great deal of water, but 50 years on the details remain sketchy. It is still unclear, for example, how a primordial soup of simple molecules could give rise to today's system of DNA and proteins. It is a classic chicken-and-egg problem: DNA codes for the proteins that catalyse the chemical reactions that replicate DNA. How could one exist before the other?”
Source: New Scientist Sept. 2004