Lazzaro Spallanzani was an Italian Catholic priest, biologist and physiologist who made important contributions to the experimental study of bodily functions, animal reproduction, and animal echolocation. His research on biogenesis paved the way for the downfall of the theory of spontaneous generation, a prevailing idea at the time that organisms develop from inanimate matters, though the final death blow to the idea was dealt by French scientist Louis Pasteur a century later.
His most important works were summed up in his book Experiencias Para Servir a La Historia de La Generación De Animales y Plantas, published in 1786. Among his contributions were experimental demonstrations of fertilisation between ova and spermatozoa, and in vitro fertilisation.