They did not know about the relationship between the ovum and the period because the discovery of ovum is not even 200 years old.
So the question stands:
*Does anybody know why the Church’s fathers asked for the procreative sex?
If they knew about the sperm, ovum and its relationship to periods would they ask for sex only in the fertile periods?
*
St. Clement of AlexandriaTo have coitus other than to procreate children is to do injury to nature
- The Instructor of Children 2:10:95:3, 191 A.D.St. AugustineFor thus the eternal law, that is, the will of God creator of all creatures, taking counsel for the conservation of natural order, not to serve lust, but to see to the preservation of the race, permits the delight of mortal flesh to be released from the control of reason in copulation only to propagate progeny.
- Against Faustus 15:7 22:30, 400 A.D.
As stated by the Catholic Church in 1880 defining NFP (with my translation), there must be honorable motives and mutual consent to use NFP:
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De uso exclusivo temporum agenneseos:
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Qu.:An licita in se sit praxis coniugum, qui, cum ob iustas et graves causas prolem honesto modo evitare malint, ex mutuo consensu et motivo honesto a matrimonio utendo abstinent praeterquam diebus, quibus secundum quorundam recentiorum theoremata ob rationes naturales conceptio haberi non potest?"
“
Resp.: Provisum est per Resp. S. Paenitentiariae,
16. Iun. 1880.”
On the exclusive use of the agenesic (sterile) period:
Whether licit in itself is the practice by which for just and grave causes, wishing to avoid offspring in a honorable way, from the matrimonial use abstain, by mutual consent and with honorable motives, except on those days which, according to certain recent theories, that for natural reasons conception is not possible.
This is as Pope Pius XII states, because:
The matrimonial contract, which confers on the married couple the right to satisfy the inclination of nature, constitutes them in a state of life, namely, the matrimonial state. Now, on married couples, who make use of the specific act of their state, nature and the Creator impose the function of providing for the preservation of mankind. This is the characteristic service which gives rise to the peculiar value of their state, the bonum prolis. The individual and society, the people and the State, the Church itself, depend for their existence, in the order established by God, on fruitful marriages. Therefore, to embrace the matrimonial state, to use continually the faculty proper to such a state and lawful only therein, and, at the same time, to avoid its primary duty without a grave reason, would be a sin against the very nature of married life.
Serious motives, such as those which not rarely arise from medical, eugenic, economic and social so-called “indications,” may exempt husband and wife from the obligatory, positive debt for a long period or even for the entire period of matrimonial life. From this it follows that the observance of the natural sterile periods may be lawful, from the moral viewpoint: and it is lawful in the conditions mentioned. If, however, according to a reasonable and equitable judgment, there are no such grave reasons either personal or deriving from exterior circumstances, the will to avoid the fecundity of their union, while continuing to satisfy to the full their sensuality, can only be the result of a false appreciation of life and of motives foreign to sound ethical principles.
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