After a revision of literature regarding the most up-to-date points of view about the etiopathogenesis of prostatic hyperplasia, i.e. hormonal growth factors, Mac Neal's theory of reawakening, and the theories based on the involvement of staminal cells, the authors report their practical experience on this subject. Since 1989 they have prepared in-vitro cultures, standardized the method and have cultivated cells with different concentrations of testosterone and growth factors. Analyses were by direct observation, with cytologic and immunochemical preparations for morphologic characterization and using the autoradiographic method to determine the Labeling Index. From a preliminary survey of the results it seems that DHT does not affect the multiplication of cells, but influences the differentiation process, becoming an agent of “well-being” and not a real growth factor. EGF would be efficacious only at high dosages with a result of non differentiation and growth of non-mature cells. The estrogens do not increase the succesful percentage of secondary cultures and are therefore, not factors of cellular “well-being”. Finally, data confirm that BPH is not a proliferative disease, as the DNA in replication is limited to about 3% with scarce mitosis.