Argument from abiogenesis
The argument from abiogenesis concerns the origin of the earlies life forms from non-living matter, known as "abiogenesis". The exact process of abiogenesis is unknown and an ongoing area of research in the chemical sciences. Though many concepts about the beginning of life have been proposed and even demonstrated, and there is a rough framework for the overall stages of the process, as of yet, a standard model of abiogenesis has not been developed.
The term "abiogenesis" was coined in 1870 by Thomas Henry Huxley, an advocate for Charles Darwin's theory of evolution. It comes from the ancient Greek "a-" (not) + "bios" (life) + "genesis" (origin). That is, the origin of life from non-life. Some confusion has arisen from the fact that the term has been used to describe the archaic theory that complex life can arise from non-life, such as maggots growing in meat. This is not the sense in which the word is used by modern researchers. Equivocating the archaic and modern usage in an attempt to discredit a modern theory is a straw man argument.
Creationists often claim that since abiogenesis could not naturally occur, it required the intervention of a designer.
Abiogenesis vs. evolution
Abiogenesis should not be confused with evolution, the study of how living things change over time, or cosmogony, the study of the origin of the universe. While evolution explains how self-replicating entities change over time, abiogenesis is the study of how self-replicators arose in the first place, and how evolution got started. It is thus related to evolution, but distinct.
- "Early on [evolution’s current view of]-abiogenesis was an integral part of evolution. [evolution’s current view of]-illusionists thought that 'spontaneous generation' of life would be found to occur everywhere on earth. That was shown to not be the case. [...] They now say that [evolution’s current view of]-abiogenesis is not part of evolution. "
The historic relationship between scientific concepts is irrelevant and (ironically) commits the genetic fallacy. What matters is the current understanding of these concepts. In principle, God could could have created simple life and allowed evolutionary processes to take their course, or both both theories could be false, or both true. Attempting to link them, then disprove one to disprove the other is a non sequitur.
This argument amounts to "I known see how abiogenesis could have happened, so it didn't happen". It is an argument from ignorance.
Life replicates itself in an either identical or nearly identical form, which distinguishes it from non-living matter. The first replicator, while simpler than modern life forms, was complex and unlikely to occur by chance or natural processes. Therefore, some intelligent intervention was required to get life going. 
No spontaneous generation of complex life
Creationists often claim that Francesco Redi disproved abiogenesis in 1668 by showing that flies do not appear on meat if the meat is sealed from outside contamination. This idea often manifests in the so-called Peanut Butter argument against evolution. In fact, Redi disproved the theory of spontaneous generation, the idea that fully-formed modern flies spontaneously arise from meat.
After the invention of the microscope by van Leuwenhoek in 1683 and the subsequent discovery of bacteria it was thought that abiogenesis occurred among microscopic creatures. In the nineteenth century, Louis Pasteur sterilized broth by boiling for fifteen minutes and then sealed it in a glass flask. After several months he noticed that dust had settled on the flask, but no micro-organisms had formed within the broth.
Current models of abiogenesis make no such claim. Rather, researchers try to figure out which organic molecules could have been formed under the conditions of the early Earth, how they might have combined to form RNA, DNA, cell membranes, metabolism, etc.
Perhaps the simplest argument for abiogenesis is:
- The Earth formerly did not have life.
- More recently, life exists on earth.
- It is scientific to assume only natural processes occurred.
- Therefore, abiogenesis occurred (or possibly panspermia).
Since evidence indicates life arose about 3.7 billion years ago, it is very difficult to find fossil remains of the earliest life forms. Many chemicals thought to have played a part in the origin of life do not last long under the conditions which they may be found today. The rocks where they might otherwise be found might have been contaminated by geologic processes, and many of them may have been subducted into the Earth's mantle. Nonetheless, there are numerous hypotheses as to how life could have arisen.
Some researchers believe that life arose on the surface of the Earth, perhaps as an oily film on the surface of the ocean, or in calmer tidal pools; the surface is, after all, where most living things are found today. Others argue that the surface of the early earth was bombarded with ultraviolet rays that would have broken down organic molecules almost as soon as they were formed, and thus these molecules could not have accumulated in sufficient concentrations to permit interesting reactions to take place.
It is also possible that life arose deep under the ocean, protected from ultraviolet rays, around hydrothermal vents. These could have provided the energy, in the form of heat, necessary for chemicals to form and react with each other.
Some of the chemicals required for life may have fallen to Earth in meteorites. Many chemicals, including sugar and alcohol, can form in gas clouds in outer space, and may therefore have been part of the composition of the Earth from the very beginning of its formation. Others may have fallen to Earth later. Meteorites known as carbonaceous chondrites contain many types of organic molecules, even after falling through the atmosphere and crashing to Earth.
It is hypothesized that minerals, including clays, may have played a role in the origin of life: if certain amino acids become attached to a clay surface, the clay in effect holds them in place, allowing other amino acids to become attached to the original ones.
Other minerals have microscopic pores, which may have been filled with interacting molecules, thus in effect playing the role of a primitive cell wall. However, it is known that lipids can spontaneously form hollow spheres in water. Thus, it is not clear whether metabolism came before cell membranes or vice-versa.
It is possible that we will never know exactly how life arose on Earth, but it may be possible to come up with a handful of likely scenarios.
The Urey-Miller experiment
In 1951, Harold Urey and his graduate student Stanley Miller conducted a seminal experiment: they filled a glass vessel with water, methane, ammonia, and hydrogen, by which they hoped to model the ocean and early atmosphere of the Earth (note that today we have a different picture of the composition of the early atmosphere). Two electrodes in the vessel produced sparks, simulating lightning. The vessel was connected by a tube to a condenser and a second chamber, from which samples could be withdrawn and analyzed.
Within a few days, the water turned yellow and dark "muck" had appeared on the walls of the vessel. This turned out to contain glycine, an amino acid. Later on, several other amino acids and other organic molecules were found.
Later experiments not only confirmed the results of the Urey-Miller experiment itself, but expanded on it, showing that many organic molecules are easy to synthesize under a wide variety of conditions, including different atmospheric compositions and energy sources.
Miller and Urey did not create life in the lab, of course, nor does anyone claim that they did. They did, however, demonstrate that molecules essential to living beings can form naturally under likely conditions of early Earth.
One common creationist argument is that the Urey-Miller experiment only created a few of the amino acids used by life, not life itself. Another is that the gases used by Miller and Urey were different from those actually present on primordial Earth.
Researchers were able to reanalyze the residues from one of the original experiments, and found several amino acids that instruments in the 1950s were not sensitive enough to detect.  In other words, Miller and Urey were more successful than they realized.
The paper also argues that the atmosphere used in that experiment may have been locally realistic. That is, that mixture of gases would not occur throughout the planet, but only near volcanic eruptions.
Later studies during the 1960s by Joan Oró, et al., that used atmospheric conditions that better match the actual (hypothesized) atmosphere of early Earth turned out to give even better results, turning up for example adenine, which is one of the nucleotide bases that form the "backbone" of DNA.
Self replicating machines
John von Neumann proposed a theoretical self-replicating machine which used surrounding resources to produce further copies of itself. Although different from living cells in many respects, it showed that a relatively simple logical system could propagate itself in an appropriate environment.
Panspermia is a speculative theory that considers life on Earth to have originated elsewhere, developed and arrived on Earth from space. It is an alternate to the abiogenesis theory but still relies on natural processes. The obvious question it raises is where and how did like originate first? This is hard to resolve definitively in the short term because it may require seeking for life elsewhere in the universe. However, it is almost impossible to rule this possibility out, so the argument from abiogenesis will remain in doubt.
Not enough evidence
The form that the first replicator might have taken and the environment in which it arose is unknown. It is therefore impossible to claim to any degree of certainty that it is unlikely to have arisen, because estimating the likelihood depends on unknown information. Since the argument fails to rule out other possibilities, it is an argument from ignorance.
Regarding the evidence for abiogenesis, we must remember that the event occurred billions of years ago. Also, it probably occurred at a molecular scale. For this reason, we might not expect much direct evidence of abiogenesis. Just because evidence of an event is not available does not make an event impossible. Science is continually progressing may way well discover direct evidence of abiogenesis. Since this argument would collapse completely in that eventually, it is a form of God of the gaps.
Simple systems can self replicate
In certain circumstances, very simple atoms and molecules can self replicate or exhibit structure, such as in crystals or snow flakes. Give that life probably began by a simple self replicating modules, this makes abiogenesis relatively more likely (although it is still hard to determine the probability of abiogenesis in absolute terms). 
Plenty of opportunity
Even if abiogenesis is only a slim possibility, it has plenty of opportunity for that to occur.
There are potentially millions of planets in the habitable zone of stars in our galaxy  and there are billions of galaxies. Only considering Earth when considering the likelihood of abiogenesis commits the Texas sharpshooter fallacy.
Experiments that attempt to replicate the conditions of the early Earth find that many important chemicals, such as amino acids, occur naturally without life. The oceans and surface of the Earth is large, providing many opportunities for abiogenesis. Also, planets exist for billions of years; the Earth is already 4.5 billion years old, which gives plenty of opportunities for abiogenesis.
- Main Article: Which God?
No specific God or religion is supported by the argument.