12. With regard to the treatment of infertility, new medical techniques must respect three fundamental goods: a) the right to life and to physical integrity of every human being from conception to natural death; b) the unity of marriage, which means reciprocal respect for the right within marriage to become a father or mother only together with the other spouse;[19] c) the specifically human values of sexuality which require “that the procreation of a human person be brought about as the fruit of the conjugal act specific to the love between spouses”.[20] Techniques which assist procreation “are not to be rejected on the grounds that they are artificial. As such, they bear witness to the possibilities of the art of medicine. But they must be given a moral evaluation in reference to the dignity of the human person, who is called to realize his vocation from God to the gift of love and the gift of life”.[21]
In light of this principle, all techniques of heterologous artificial fertilization,[22] as well as those techniques of homologous artificial fertilization[23] which substitute for the conjugal act, are to be excluded. On the other hand, techniques which act as an aid to the conjugal act and its fertility are permitted. The Instruction "Donum Vitae" states: “The doctor is at the service of persons and of human procreation. He does not have the authority to dispose of them or to decide their fate. A medical intervention respects the dignity of persons when it seeks to assist the conjugal act either in order to facilitate its performance or in order to enable it to achieve its objective once it has been normally performed”.[24] And, with regard to homologous artificial insemination, it states: “Homologous artificial insemination within marriage cannot be admitted except for those cases in which the technical means is not a substitute for the conjugal act, but serves to facilitate and to help so that the act attains its natural purpose”.[25]
[19] Cf. Congregation for the Doctrine of the Faith, Instruction Donum vitae, II, A, 1: AAS 80 (1988), 87.
[20] Congregation for the Doctrine of the Faith, Instruction Donum vitae, II, B, 4: AAS 80 (1988), 92.
[21] Congregation for the Doctrine of the Faith, Instruction Donum vitae, Introduction, 3: AAS 80 (1988), 75.
[22] The term heterologous artificial fertilization or procreation refers to “techniques used to obtain a human conception artificially by the use of gametes coming from at least one donor other than the spouses who are joined in marriage” (Instruction Donum vitae, II: AAS 80 [1988], 86).
[23] The term homologous artificial fertilization or procreation refers to “the technique used to obtain a human conception using the gametes of the two spouses joined in marriage” (Instruction Donum vitae, II: AAS 80 [1988], 86).
[24] Congregation for the Doctrine of the Faith, Instruction Donum vitae, II, B, 7: AAS 80 (1988), 96; cf. Pius XII, Address to those taking part in the Fourth International Congress of Catholic Doctors (29 September 1949): AAS 41 (1949), 560.
[25] Congregation for the Doctrine of the Faith, Instruction Donum vitae, II, B, 6: AAS 80 (1988), 94.