STERILITY. — The term, related to that of impotence, is used in medico-legal language to indicate a particular defect in the efficacy of the procreative function.
Impotence and s. designate the concepts of two different defects and juridical situations both in canon law and in civil law, while the paramount importance of a clear delimitation of their respective objects is apparent from the fact that the legitimacy and validity or nullity of marriage is linked to proof of one or the other (“Impotentia... matrimonium ipso naturae iure dirimit... Sterilitas matrimonium nec dirimit nec impedit”: CIC, can. 1068). If, however, in common understanding and language the difference in their respective conceptual content appears readily, in the juridical sphere, following the views of the different currents and schools, it is no easier to establish a clear boundary between impotence and s. Their boundaries are often confused and almost disappear, with part of their contents being exchanged; thus, while the meaning of one broadens, that of the other narrows, and the terminology becomes confused, not only in the comparison between civil law and canon law, but within one and the same legal system. On the question, V. IMPOTENZA.
In order, therefore, to preserve the exact distinction between the terms and thus not confuse s. with impotence, it must be said that a sterile person is not one who is incapable of performing the conjugal act according to the order of nature, but one who is indeed able to perform it, although generation cannot result from II. Therefore the CIC establishes that s. neither annuls nor impedes marriage (can. 1068 § 3); hence even persons of advanced age may contract marriage, provided that they are able to consummate the marriage itself. In other words: there is impotence when the capacity to consummate the marriage is lacking; s. when this power is not lacking, but the effect of the power is lacking—an effect which would not be absent if its cause were found in those circumstances in which alone it could exercise all its power and produce the effect (generation) for which it is intended. Where impotence exists, the conjugal act cannot take place; where s. exists, the act can take place, but without its effect (cf. T. A. Iorio, Theol. mor., III, 3ª ed., Napoli 1947, n. 1061).
1. Physiological periodic s. as the basis of the method of periodic abstinence. - The period of time between the first day of one menstruation and the first day of the immediately following one constitutes in a woman the “sexual cycle”; taking part in it through characteristic phenomena are not only the ovary and uterus, but the entire organism, including its highest psychic functions. With regard to the ovary, what is of interest is the periodic maturation of the ova, which occurs at determinate times, almost constant for each woman. The ova, preformed at birth and arrested in the embryonic state in a number numbering several tens of thousands, reach maturity, normally one at a time, cycle by cycle, throughout the period extending from puberty to menopause (v. ETÀ CLI-
MATERICHE); thus only 400–450 ova become capable of fertilization over a period of approximately 30–35 years, the duration of a woman’s sexual life. For this reason, a woman is physiologically sterile before puberty and after menopause; periodically physiologically sterile during the intervals between the maturation of one ovum and that of the next. With regard to the modifications affecting the uterus, what is of interest is the periodic destruction of the uterine mucosa (endometrium) at the close of each sexual cycle in which the ovum was not fertilized; this is plainly indicated by a more or less abundant and prolonged hemorrhage (menstruation), signifying that the intense proliferation and congestion of the uterine mucosa, preordained for the implantation of the fertilized ovum, was not utilized because of the failure of the fusion of the two sexual elements and the rapid death of the ovum. The appearance of menstruation thus becomes an easily recognizable external sign delimiting the closing of one sexual cycle and the beginning of the next, as well as of the inutilization of the ovum.
Contrary to what was formerly admitted, when it was held that the liberation of the mature ovum from the surface of the ovary (ovulation) took place during the hemorrhagic phase of the cycle (the hypothesis of Pouchet-Pflüger, 1840, followed by the German gynecologist A. Capellmann in his Medicina pastoralis, Paris 1893), it is now securely recognized that, under normal conditions, ovulation occurs approximately in the middle of the cycle if this lasts an average of 28 days, or, more generally, between the 12th and 16th day preceding the beginning of the next cycle. The merit for this discovery and its demonstration belongs to the Japanese Kyusahu Ogino and the Austrian Hermann Knaus, who, proceeding by different paths, at successive times (1924–29), but without knowledge of one another, established for science the true chronology of ovulation. For the reason stated above, in view of the woman’s brief period of fertility, which, within the few days during which ovulation may occur, is essentially reduced to two hours and a little more, such being the duration of the ovum’s extremely brief life, there exist, during the remainder of the sexual cycle, before and after, at its beginning and end, two periods of physiological periodic s. of unequal length. The pre-ovulatory period, or period of post-menstrual s. (from the first appearance of menstruation to the rupture of the Graafian follicle enclosing the ovum on the point of maturation), comprises the phase of development of the ovum; the post-ovulatory period, or period of pre-menstrual s., will eventually be occupied by the meeting of the two sexual elements, by fertilization, and by the migration of the fertilized ovum toward uterine implantation; or, conversely, in it will occur the death of the ovum that has failed to be fertilized, while the vainly expectant endometrium, which was ready to receive it and is now unused, proceeds toward menstrual destruction. The two aforementioned phases of the cycle correspond to two different endocrine orientations and equilibria (v. ENDOCRINE, GLANDOLE), which influence the woman’s entire bio-psychological balance through both functional and structural modifications. While the first phase is governed by the secretion of the follicle (the follicular phase of the sexual cycle), the second is governed by the hormonal secretion of the “corpus luteum” (the luteal phase), which has formed in the empty cavity of the ruptured follicle. A higher regulation of this mechanism is connected with the anterior pituitary and the sexual nervous centers of the diencephalon.
The nature and limits of the entry prevent a more extensive theoretical treatment and the scientific demonstration of the facts asserted, which may be obtained from the study of the specialized works cited in bibl. Here it is enough to say that, on the basis of an exact knowledge of the development of the female sexual cycle and of the moment of ovulation, of knowledge of the ovum’s extremely brief life and of the limited possibility of waiting and survival of the male sexual elements after their emission (after approximately 30–48 hours the spermatozoa lose motility and fertilizing capacity and die), it is possible to base a system of birth control: the method of periodic abstinence, improperly called the “Ogino-Knaus method,” which more properly bears the name “Smulders method,” after the Dutchman J. M. J. Smulders (d. 1939), who, with skill and prolonged patience, from 1930 until his death, developed it, disseminated it, and tested it on the basis of the aforementioned scientific discoveries of Ogino and Knaus. He collected a large number of observations and practical experiences in order to make it increasingly exact and reliable, and it may be said that all the variations subsequently introduced by others do not in the least alter its foundations or the substance of its practical application.
The method of periodic abstinence, according to Smulders, rests on the following basic principles: 1) the ovum is mature and free, ready to be fertilized, only between the end of the follicular phase and the beginning of the luteal phase, and preserves its vitality only for an extremely brief period of time (approximately 2 hours); 2) the fertilizing capacity of the male sexual elements does not exceed 30–40 hours; 3) calculation of the woman’s period of fertility must always be made backward from the probable date of the future menstruation, which, being a future and uncertain event, can be fixed presumptively by determining it from the average lengths of a certain number of past cycles. This is the most delicate and uncertain part of the method of periodic abstinence, on which all the ingenuity of its defenders and disseminators is directed and at which most of the method’s opponents’ criticisms are aimed. If the length of the sexual cycle, although different for each woman, were for each one a fixed constant, it would be easy and reliable to establish the recurrence of the few fertile days; on the contrary, every woman, although tending to settle into a determinate cycle length (between minimums of 20–22 and maximums of 34–36 days, with an average, according to Arey’s statistics conducted on 20,000 cycles, of 29 days), undergoes fluctuations in her period which, following the characteristics of fluctuating variability, shift within margins of 2–5 days’ difference. It will be seen further on how, in applying the method, it is possible to compensate for the shifts undergone by the fertile period as a result of the continual oscillation in cycle length.
2. Technique of the method
Through observation of the variability of the sexual cycles over a sufficiently long period (possibly 10–12 months), the maximum limits of their fluctuations in length are established (for example, if the shortest period observed is 26 days and the longest 30 days); it is understood that this already entails in advance the need for a margin of four days (30–26=4) to be added to the period of presumed fertility of the woman. This period consists, as its basis, of the five days within which ovulation may fluctuate (the 12th, 13th, 14th, 15th, and 16th days before the subsequent menstruation), plus the two preceding days during which the spermatozoa may possibly survive and await (the 17th and 18th), plus one further day (the 19th), included, according to some, as an additional margin of prudence in view of exceptionally early ovulations or longer spermatozoal vitality, or, according to others, as a margin of partial compensation for the inevitable differences in time involved in establishing, with the approximation of a day, the beginning of the cycle. Thus, in all, eight days during which conception might occur. In the example given, therefore, there results a period of possible fertility of 12 days (4+8), situated in the transitional portion between the follicular and luteal phases of the sexual cycle. Placing this period in the middle of the cycle leads to a fixed period of premenstrual s. comprising the final 11 days of the cycle, and to a postmenstrual period of s. extending from the beginning of the cycle to the 19th day (excluded before the future return). Whereas the premenstrual period of s. always retains a fixed length of 11 days, the postmenstrual period varies in length, in relation to the differing length of the cycle. Thus, for example, whereas in a 26-day cycle it will be 7 days (26–19=7), in a 30-day cycle it will be 11 days (30–19=11). Since the length of the next cycle is uncertain, the nearest limit must be presumed, that is, the period of s. must be made to end on the 7th day, and the final 11 days of s. must be calculated on the basis of the longest cycle; conception must therefore be regarded as possible from the 8th day through the 19th, inclusive, counting from the beginning of the cycle then in progress.Many objections have been raised against the method, of such a kind as to appear seriously to undermine its basis and the results hoped for; we shall recall the principal ones. The considerable irregularity of the cycles, particularly during certain periods of a woman’s life (the climacteric, the post-puerperal period, lactation, intercurrent illnesses, convalescence, etc.), may make the period of fertility very long and uncertain and, correspondingly, the periods of s. short and indeterminable; sudden physical and psychic traumas may disturb the regularity of the cycles; and there is the possibility of supernumerary ovulations outside the period established by the investigations of Ogino and Knaus. All these circumstances could be such as to deprive the periods of physiological s. of any security.
We cannot here undertake a detailed refutation of the objections mentioned above; it may, however, be stated without hesitation (v. BIBLICA), that the great majority of women, particularly during the central period of their sexual life, are capable of applying the method of periodic continence extremely well, even without recourse to particular advice from a specialized physician, provided that they apply intelligently, accurately, and cautiously the rules set forth in the best books on the method. Without doubt, there are cases and circumstances in which application of the rules becomes difficult and even fallacious, and is not possible on the basis of calendrical methods alone: here the work of a specialist in the field is required. Through clinical study of the case, resorting to careful examination of the concomitant phenomena (intermenstrual crises, the temperature curve, direct examination of the collateral cyclical phenomena of ovulation), employing the necessary means to restore any function that may have been altered, and following month by month the anomalies of rhythm and the chance interference of disturbing factors, the specialist may succeed in giving the method of periodic continence accuracy and security.
3. Statistical examination of the results
A critical study of the practical results represents the most compelling evidence of the value of the method of periodic continence; here one may draw upon the experience of thousands of favorable cases, with which the statistics of honest and careful investigators abound. In contrast, its opponents for the most part produce only isolated cases, often not even their own, poorly studied and lacking reliable clinical elements on which a scientifically valuable criticism can be based. To these may be opposed, besides the data of Smulders, so carefully studied and described, the statistics of Miller, Schultz and Anderson (Conception Period in normal Adult Women, in Surg. Gynecol. Obst., June 1933, pp. 1020–25, Chicago); of Leo Latz (The Journal of the Amer. Med. Assoc. pp. 1241–46, Chicago 1935); of Carvalho Azevedo (Das Problem der bewussten Befruchtung, in Ann. Brasil. Gynec., Rio de Janeiro 1936, pp. 255–83); of J. G. Holt (in Nederl. Tijdschr. V. GELÉE, CLAUDE, 1941, 8 Nov., no. 45); etc. Stecher’s book (op. cit. in BIBL., p. 106 ff.) reports a lengthy observation made in a married couple over no fewer than 17 years of practicing the method; despite 3,000 acts of intercourse, only three conceptions occurred: one before the application of periodic continence began, and the other two (at intervals of 16 months and three and a half years) deliberately obtained. Prof. C. G. Hartman of the Carnegie Institution of Washington, in Birth Control Review (May 1933), states, on the basis of experience, that the method of periodic continence, when properly applied, provides at least as much security as the more widely publicized contraceptive methods recommended by American marriage counseling services. Since these are facts that unfold on the biological plane and are therefore subject to all the alternatives of fluctuating variability, and to the interference of all individual, social, and cosmological causes capable of continually acting upon the vital manifestations of the individual, there is no doubt that it is impossible to establish absolutely, by means of a numerical index, the percentage probability of the method’s success. One may speak of 100% success for it, as of 90% (Dickinson) or 80% (Dervaique and Seguy), or of considerably higher failure rates if it is poorly applied or used under particular conditions that only the physician can evaluate and control (the woman’s physical health; the equilibrium of her sexual, neurovegetative, endocrine, and higher neuro-affective functions).One may therefore conclude positively regarding the value of the method of periodic continence and attribute the failures reported in certain common cases to the causes mentioned above, occurring outside the guidance of the specialized physician.
4. Moral question
Without any doubt, the Church has always condemned all those forms of neo-Malthusianism that seek to control births by vitiating the natural mechanism of the marital act (v. NEO-MALTHUSIANISMO). But in reality, the method of periodic continence cannot directly fall under such condemnations, since in it, apart from the voluntary choice of the periods of physiological periodic sterility, the act is performed according to the natural process, without the intervention of elements extrinsic to it that would intrinsically vitiate II. For this reason, the morality and possible liceity of the acts performed concern, rather than the particular means employed, the end that the subject proposes, the motives by which he is moved, and the circumstances in which the act takes place. Now, provided that the subject uses marriage according to the natural order established by the Creator, he may use it even if the end does not coincide with the primary one (procreation), provided that the end he proposes is objectively honest or corresponds to the secondary ends of marriage (the growth of mutual love, mutual assistance, satisfaction of instinct, etc.). Such circumstances undoubtedly render the use of marriage generically lawful, indifferently in any period and also in those circumstances in which the woman is certainly sterile, such as during pregnancy and after menopause has occurred (even more generally, the CIC, can. 1068, states: Sterilitas matrimonium nec dirimit nec impedit). This, however, particularly in the view of some moralists (P. Salsmans in Ephemerides Theologicae Lovanseense, 1934, pp. 562–70), cannot automatically lead to the admission of the liceity of periodic continence, since in it there is the particular positive element of choosing certain days and the deliberate exclusion of others, in order to avoid procreation; in this way, the hierarchical relations among the ends of marriage would be altered, with the secondary ends being made to prevail over the primary ones.Already, however, the majority of moralists (I. P. Gury, A. Ballerini, H. Noldin, A. Lehmkuhl, P. Gasparri, I. Ferreres, E. Génicot, J. Ubach, A. Vermeersch, F. Hürth, etc.) admitted the liceity of periodic continence, which does not invalidate the object of marriage but merely changes its subjective circumstances; consequently, the matters to be judged with regard to liceity become the intention, the motives determining it, and the circumstances in which it is put into practice (cf. A. Vermeersch, Periodica de re morali, 1934, p. 241). Also belonging to the past are two responses of the Holy Penitentiary (in the years 1853 and 1880); in them it is said that those spouses who limit the use of marriage to periods in which fertilization is more difficult or impossible are «inquietandos non esse», provided that they do nothing to prevent conception.
But every dissenting opinion among moralists must now be considered nullified in the face of the clear judgment repeatedly and authoritatively given by Pope XII in his address to the participants in the Congress of the «Unione Cattolica Italiana Ostetriche» (29 Oct. 1951): «If the implementation of the theory is intended to signify nothing more than that spouses may exercise their matrimonial right also on days of natural sterility, there is nothing to oppose; by this, in fact, they neither prevent nor in any way prejudice the consummation of the natural act and its further natural consequences... If, on the other hand, one goes further, allowing the conjugal act exclusively on those days, then the conduct of the spouses must be examined more carefully... If the limitation of the act to days of natural sterility refers... only to the exercise of the right... the moral liceity of such conduct by the spouses would have to be affirmed or denied according as the intention of constantly observing those periods is or is not based on sufficient and certain moral motives. The mere fact that the spouses do not offend against the nature of the act and are also ready to accept and educate the child who, despite their precautions, might be born would not in itself suffice to guarantee the uprightness of the intention and the unimpeachable morality of those motives... The marriage contract, which confers upon the spouses the right to satisfy the inclination of nature, places them in a state of life, the matrimonial state. Now, for spouses who make use of it through the specific act of their state, nature and the Creator impose the function of providing for the preservation of the human race. This is the characteristic obligation that constitutes the proper value of their state, the bonum prolix... Therefore, to make continual use of the faculty proper [to the matrimonial state] and lawful only within it, while, on the other hand, always and deliberately evading, without serious reason, its primary duty, would be to sin against the meaning of married life. Serious motives, such as those found not infrequently in the so-called medical, eugenic, economic, and social “indication,” may dispense from that obligatory positive obligation, even for a long time, indeed for the entire duration of the marriage. From this it follows that the observance of infertile periods may be lawful from the moral standpoint; and under the conditions mentioned it actually is so. If, however, according to a reasonable and equitable judgment, there are no such serious personal reasons or reasons arising from external circumstances, the will habitually to avoid the fecundity of their union while continuing fully to satisfy their sexuality can arise only from a false appreciation of life and from motives foreign to the proper ethical norms» (AAS, 43 [1951], pp. 845–46). And in the subsequent address to the «Fronte della famiglia»: «The Church knows how to regard with sympathy and understanding the real difficulties of married life in our own day. Therefore, in our latest address on conjugal morality, we affirmed the legitimacy and at the same time the limits, in truth very broad, of a regulation of offspring which, unlike the so-called “birth control,” is compatible with the law of God. Indeed, one may hope (although in this matter the Church naturally leaves the judgment to medical science) that the latter will succeed in providing that lawful method with a sufficiently secure foundation, and the most recent information seems to confirm such a hope» (AAS, 43 [1951], p. 859).
BIBLI: R. De Guchteneers, Les variations cycliques de la fécondité féminine, in Rev. franç. de gynéç. et d'obstr., Parigi 1913, pp. 138-57; id., A propos de la continence pérol., in Saint Luc médical, Bruxelles 1939, n. 3, pp. 194-207; K. Ogino, Conception period of women, Harrisburg (USA) 1934; J. N. Smulders, Periodiche Onthouding in het Huuselijk, 7ª ed., Nijmegen-Utrecht 1934; A. Mayrand, Un problème moral: la continence pérol. dans le mariage, suivant la méthode Ogino, Coublivie 1934; H. Knaus, Die period. Fruchtbarkeit und Unfruchtbarkeit des Weises, Vienna 1935; L. Latz, The Rhythm of sterility and fertility in women, Chicago 1935; A. Gennaro, De period. contin. matrimon., Torino 1938 (trad. it., ivi 1947); L. Oldani, Una questione viva. Ancora della contin. period. nel matrim., in La Scuola Catt., 67 (1939), pp. 363-67; J. Pujula, De medicina pastor., Torino 1948, pp. 58-66; P. Babina, Fecondità et infecondità nel matrim., Milano 1949; L. Seremin, Diz. di morale profession. per i medici, 4ª ed., Roma 1949, pp. 358-68; J. E. Georg, Agenesi e fecondità nel matrim., Torino 1950; A. Boschi, Nuove quest. matrim., 3ª ed., ivi 1950; A. Niedermayer, Handbuch der speziellen Pastoralmedizin, II, Vienna 1950, pp. 1-93 (s. periodica), pp. 95-153 (s.); G. B. Guzzetti, Sguardo stor.-mor. ai problemi della popolazione, in La scuola catt., 79 (1951), pp. 283-343; A. Stecher, Contin. period. nel matrim., Firenze 1951; A. Lanza - P. Palazzini, Theol. mor., Append. De castitate et luxuria, Torino Roma 1953, pp. 69-86; V. bibl. alle voci: MATRIMONIO, uso del; NEO-MALTHUSIANIEMO: NASCITE, controllo delle. Giuseppe de Nino