The author makes a brief historical recapitulation of the problem, from the time of Semiramis to the present, dwelling on, and summing up, the various laws which in many countries grant the State the authority to sterilize, with distinct criteria and purposes. He studies extensively the german law of 1925 with which he is not in agreement. He does not accept heredity to be the most important factor of mental diseases, for which reason, the law would lose its eugenic character. From the biological point of view, he mention of Gal ton, Mendel, Vignes, etc. to clarify his point of view, against all generalization. Besides, he refutes the economic aspect of the problem, which serves as an argument by the supportes of the sterilization doctrine. Finally, he proposes, after having cited the adverse opinion of Dr. Otolenghi, nine points to be adopted in this cooutry as substitutes for sterilization, the author believes, that is what should be done in front of this folly as a social evil.