On the other hand, some European theologians have denied that the practice constitutes a mortal sin in itself, independently of circumstances such as injustice and danger of incontinence.
The present state of opinion, then, is definitely undecided and calls for caution both in dealing too severely with penitents or too readily recommending the practice. The response of the Sacred Penitentiary of June 16, 1880, affords a safe guide in practice: “Married couples who use their marriage rights in the aforesaid manner are not to be disturbed, and the confessor may suggest the opinion in question, cautiously, however, to those married people whom he has tried in vain to dissuade from the detestable crime of onanism.”
As to the theological censure to be attached to “rhythm,” it is not approved, nor recommended, but seems to be tolerated for sufficiently grave reasons. “Instead of being freely taught and commended, it is rather to be tolerated as an extreme remedy or means of preventing sin” (Official Monitum, Patrick Cardinal Hayes, Sept. 8, 1936, _Conference Bulletin of Archdiocese of New York_, Volume XIV, No. 2, p. 78).
2623. Cooperatio Uxoris ad Onanismum vel Contraceptionem.—(a) Cooperatio formalis graviter illicita est, quum includat approbationem ipsius peccati. Unde graviter peccat uxor quae suis quaeremoniis de molestiis graviditatis virum cogit ad congressum onanisticum, vel quae nec interdum conatur eum avertere ab iniquo consilio onanistice congrediendi, vel quae active adjuvat abruptionem copulae, vel quae interne gaudet de ipso peccato (1513).
(b) Cooperatio materialis ad onanismum ex gravi causa (e.g., ex metu fundato rixarum, molestae cohabitationis, adulterii viri) licet; nam actio mulieris, scil. copulam habere naturalem, honesta est, atque causa sufficiens adest permittendi abusum factum a comparte (1515 sqq.). Imo uxor debitum petere potest a suo viro onanistico, si secus diu abstinere cogeretur ab omni usu conjugii cum periculo incontinentiae, quia caritas erga virum non obligat ad abstinentiam cum tanto incommodo.
(c) Cooperatio mere materialis ad contraceptionem, non videtur possibilis; nam copula contraceptiva est intrinsece et ab initio mala (1517, 1527). Unde uxori nec petere debitum licet, nec passive se habere. Sed qualibet vice tenetur positive pro viribus resistere. Sin autem gravissima causa sit actum permittendi, ut puta periculum mortis, eam tantum resistentiam opponere debet ad quam obligatur virgo oppressa (2497), consensu ut patet denegato (See _Irish Ecclesiastical Record_, June, 1940, pp. 634 ff., and March, 1948, pp. 244 ff.)
2624. Recapitulatio de Licitis et Illicitis in Conjugio.—(a) Illicita graviter sunt extra matrimonium facta, v.g., moechia, mollities solitaria, alienae conjugis concupiscentia; sed probabiliter actus imperfecti et solitarii in proprium corpus exerciti leve non excedunt, citra periculum pollutionis, siquidem in delectationem veneream quae in conjugio licita est natura sua ordinentur, sicque minus indecentes fiant.
(b) Illicita graviter sunt intra matrimonium facta sed contra finem, i.e., naturae matrimonii seu generationi prolis repugnantia, ut sunt pollutio mutua, onanismus, impudicitia quae non in copulam sed in pollutionem tendit.
(c) Illicita leviter sunt intra matrimonium facta sed praeter finem, i.e., qum generationi nec prosunt, nec obsunt, sed in circumstantiis aliquam prae se ferunt inordinationem (e.g., copula ob solam voluptatem habita), imprudentiam (e.g., copula tempore parum apto habita), immoderantiam (e.g., impudicitia pudori nociva, situs innaturalis, ut si stent vel vir succubet, ex levitate electus).
(d) Licita sunt intra matrimonium facta, quae tum ex parte objecti (scil., quia actus ordinatur ad finem matrimonii), tum ex parte circumstantiarum (scil., quia debito tempore, loco, modo, etc., ut prudentia exigit, exercentur) rationi rectae concordant. Unde non peccant conjuges sibi licita concupiscendo vel de iis gaudendo. Immo mulier onanistae licite cooperata non est peccati arguenda si gavisa sit de ipsa copula vel de bonis ejus effectibus, vel (saltem quando probabile videtur se semen excipisse) si ad completam voluptatem se excitaverit.