In his book The Origin of Life, Oparin proposed that the "spontaneous generation of life" that had been attacked by Louis Pasteur did in fact occur once, but was now impossible because the conditions found on the early Earth had changed, and preexisting organisms would immediately consume any spontaneously generated organism.
U svojoj knjizi Porijeklo života Oparin je predložio da se ''spontana generacija života'', koju je kao hipotezu napadao Louis Pasteur, jednom uistinu desila, ali je sada nemoguća jer su se uvjeti na ranoj Zemlji promijenili te bi postojeći organizmi odmah konzumirali bilo kakav spontano formirani organizam.