On the other hand, the Church does not consider at all illicit the use of those therapeutic means necessary to cure bodily diseases, even if a foreseeable impediment to procreation should result there from—provided such impediment is not directly intended for any motive whatsoever.
The oral contraceptive pill is used for a wide variety of reasons. In my practice, its use as a contraceptive comes about fourth on the list of reasons why I prescribe it. I mainly prescribe the pill for the treatment of endometriosis, dysmenorrhea and acne in that order. Paradoxically, and to my surprise, when used for the treatment of endometriosis it may, in fact, protect fertility! (Go figure!). Now, Catholic moral theology permits the use of the pill for medical reasons where the intention is to use the pill as a therapeutic agent and not as a contraceptive. The moral logic which permits the pill's use in such circumstances is the principle of double effect.
The doctrine of double effect has come about due to the recognition of the fact that sometimes a good action may have unintended bad effects. The classic case being the legitimacy of removing a bleeding fallopian tube in the instance of an ectopic pregnancy, and thereby causing the loss of life of the fetus.
Cynics, looking at the doctrine of double effect, have claimed that it is possible to justify anything by appeal to this doctrine. To protect against such abuse, in order for an action to be considered morally good, it must satisfy the following criteria:
- The nature-of-the-act condition. The action must be either morally good or indifferent.
- The means-end condition. The bad effect must not be the means by which one achieves the good effect.
- The right-intention condition. The intention must be the achieving of only the good effect, with the bad effect being only an unintended side effect.
- The proportionality condition. The good effect must be at least equivalent in importance to the bad effect.
How do I weigh a woman's fertility in relation to a condition like endometriosis? Or acne for the matter? Is suppressing a woman's fertility of the same order of gravity as making her go blind or is it the same order of gravity as an appendectomy?
If, as Humane Vitae asserts, the suppression of fertility is associated with grave sin, then must endometriosis be really-really bad before I can prescribe the pill? How bad is really-really bad? Or make things even more complicated, sometimes the symptoms can be out of all proportion the degree of disease on imaging or laparoscopy? Is badness a measure of the patients discomfort or the actual objective disease load? Where the dividing line is I don't know.
The problem with Humane Vitae lays in its evaluation that the the suppression of fertility is a very grave matter. This has practical implications on the treatment of medical conditions if one is to follow the full letter of the law and thereby be consistent with the principle of double effect. In order to satisfy condition no 4, the only way I could legitimately use the pill, as a therapeutic agent, is if the patient's medical condition is grave. Therefore the pill could only be justified in extreme cases. This, of course, would be a terrible outcome, since the pill is a very effective way to treat many medical conditions with minimal side effects compared to the alternatives. Menorrhagia, a condition which affects many women, would have to be treated with other agents which are less effective and have more complications than the pill. Humanae vitae, strictly applied, effectively removes a whole class of therapeutic agents except for extreme circumstances.
As far as I can see, when it comes to its application, Humanae Vitae is asymmetric in its understanding. When it comes to sexual matters, the suppression of fertility is a grave matter, when it comes to the treatment of medical conditions it is not.
(Note. One of the weirdest things I ever had to do was put a Nun on the Pill for endometriosis!)