You mean Stanley Miller's experiment, I think.
What Miller did was to place some water and some inorganic gases that he thought constituted the early Earth atmosphere into a sealed system, and introduced a spark to simulate lightning strikes. After a week, there was some chemical goo in the collection trap.
He analyzed the goo, and found amino acids, lipids, simple carbohydrates, and even some of the chemicals that are components of nucleic acids.
The debate was threefold:
1. Did Miller's experiment represent reality? That is, could this have happened on early Earth?
2. Did Miller use an appropriate mixture of gases? Is that what was really present on early Earth?
3. The biggie: Could this have led to abiogenesis (the formation of life from non-living materials?