I asked the question because of the famous Miller & Urey Experiment. I think that experiment was conducted to replicate the earliest form of life. But, what they were able to produce was only the building block of protein--amino acids.
You can read
the paper online. Its title is "Production of Amino Acids Under Possible Primitive Earth Conditions".
And, subsequent experiments also proved a failure to create even a single molecule of protein--unless they use "building blocks" from living organism ???
True. Discovering possible ways that proteins could arise abiotically is an area under research right now. Some scientists think that the first replicators may have not been proteins, but opt instead for research into simple nucleic acid such as TNA or GNA. Another area that has had interest is in proteinoids.