Even when we have gained a fairly clear conception of the stocks and the individuals which we are justified in encouraging to undertake the task of producing fit citizens for the State, the problems of procreation are by no means at an end.  Before we can so much as inquire what are the conditions under which selected individuals may best procreate, there is still the initial question to be decided whether those individuals are both fertile and potent, for this is not guaranteed by the fact that they belong to good stocks, nor is even the fact that a man and a woman are fertile with other persons any positive proof that they will be fertile with each other.  Among the large masses of the population who do not seek to make their unions legal until those unions have proved fertile, this difficulty is settled in a simple and practical manner.  The question is, however, a serious and hazardous one, in the present state of the marriage law in most countries, for those classes which are accustomed to bind themselves in legal marriage without any knowledge of their potency and fertility with each other.  The matter is mostly left to chance, and as legal marriage cannot usually be dissolved on the ground that there are no offspring, even although procreation is commonly declared to be the chief end of marriage, the question assumes much gravity.  The ordinary range of sterility is from seven to fifteen per cent. of all marriages, and in a very large proportion of these it is a source of great concern.  This could be avoided, in some measure, by examination before marriage, and almost altogether by ordaining that, as it is only through offspring that a marriage has any concern for the State, a legal marriage could be dissolved, after a certain period, at the will of either of the parties, in the absence of such offspring.

It was formerly supposed that when a union proved infertile, it was the wife who was at fault.  That belief is long since exploded, but, even yet, a man is generally far more concerned about his potency, that is, his ability to perform the mechanical act of coitus, than about his fertility, that is, his ability to produce living spermatozoa, though the latter condition is a much more common source of sterility.  “Any man,” says Arthur Cooper (British Medical Journal, May 11, 1907), “who has any sexual defect or malformation, or who has suffered from any disease or injury of the genito-urinary organs, even though comparatively trivial or one-sided, and although his copulative power may be unimpaired, should be looked upon as possibly sterile, until some sort of evidence to the contrary has been obtained.”  In case of a sterile marriage, the possible cause should first be investigated in the husband, for it is comparatively easy to examine the semen, and to ascertain if it contains active spermatozoa.  Prinzing, in a comprehensive study of sterile marriages ("Die Sterilen Ehen,” Zeitschrift fuer Sozialwissenschaft, 1904, Heft 1 and 2), states