§ 3. On Impotence for Intercourse

Those able to have intercourse, and therefore not bound by the impediment, are men who can place an act of itself apt for generation; likewise wives who are capable of admitting acts of this sort. But an act of itself apt for generation consists, on the part of the man, in this: that the man penetrates the woman's vagina and pours forth true semen there; on the part of the woman, in this: that she permits the penetration of the male member and the effusion of semen in the vagina. These things laid down, I say:

I. They lawfully have intercourse:

1. Those who are only incapable of generating, such as sterile women; or old men who lack fertile semen (St. Alphonsus VI, 1095).

2. Women who cannot retain semen.

3. Women whose uterus or ovaries have been removed. For to those to whom marriage must be permitted, the use of it is also permitted. But marriage must be permitted to the aforesaid women.¹ The final reason for affirming this, however, is that in the case the act placed is of itself apt for generation.

4. Women who have undergone oophorectomy. Oophorectomy consists in the division of the oviduct or canal by which semen is led to the ovaries; hence it only brings it about that the semen of the man cannot ascend to the ovaries, but it does not prevent its being poured forth into the vagina, or prevent an act of itself apt for generation from being placed.

87. II. It is disputed whether one who has undergone vasectomy and a castrated man lawfully have intercourse.

1. One who has undergone vasectomy. Vasectomy consists in this: that, after an incision has been made through the scrotum, the organ carrying semen elaborated by the testicles is cut away, so that the way to ejaculation is broken off for the semen. From this it follows that one who has undergone vasectomy cannot, after the emptying of the epididymis, pour forth semen into the vagina;² hence, if the completed act of venereal things is admitted, he is truly polluted.

2. A castrated man. To him both imperfect intercourse, or penetration of the vagina, and incomplete acts seem lawful. For a castrated man, by force of marriage, received and retains the right to perfect intercourse. Now the right to perfect intercourse carries with it the right both to the act which is an essential part of perfect intercourse, that is, to penetration of the vagina, and to the acts which by their nature are referred to perfect intercourse, that is, to incomplete acts.

Objection 1. No one can have a right to something unlawful. But perfect intercourse is radically and irremediably unlawful for a castrated man.

Response. Perfect intercourse for a castrated man is rather impossible than unlawful (cf. St. Alphonsus VI, 933).

Objection 2. Since a castrated man is unfit for an act of itself apt for generation, that is, since he cannot pour semen into the vagina, the insemination of the wife becomes mere pollution.

Response. Since the wife, from the act which is an essential part of perfect intercourse, that is, from penetration of the vagina, seems to receive the right to insemination, this is undeservedly called pollution. But as to the fact that the insemination of the wife is frustrated of its end, both the man and the wife permit this.

Question. Whether marriage and its use can be permitted: 1. to a man lacking testicles, into whose scrotum the testicles of an animal have been inserted, which we know sometimes has taken place; 2. to a woman for whom a vagina has been made artificially.

Response. As regards the former case, it seems that it must be answered affirmatively as soon as, in view of the declaration or doubt of an expert, the testicles must be judged at least probably to have become part of the body and to produce human semen, although infertile. Likewise as regards the other case, it seems that it must be answered affirmatively as soon as, again considering the declaration or doubt of an expert, the vagina has at least probably become part of the body (cf. can. 1068, § 1). In both cases, however, the future partner must be warned. Moreover, it is certainly to be advised that, when the case occurs, ecclesiastical authority be consulted.

¹ Cf. Sacred Congregation of the Council, December 16, 1905; Sacred Congregation for the Discipline of the Sacraments, April 2, 1909.

² Namely, those who have undergone vasectomy, and likewise castrates whose testicles have been crushed in mature age, can for some space of time emit semen kept in the epididymis; but after the said semen has been emitted, they can indeed preserve the erectability of the member and penetrate the vagina, and even ejaculate a certain liquid, but this liquid is not true semen, but some watery humor secreted by the prostate gland (De Smet, De Matrimonio, II, n. 550).