In this case, "the knowledge of women’s natural fertility cycles becomes important for the life of the married couple. Observation methods that enable a couple to determine fertility periods enable it to manage what the Maker has skilfully inscribed in the human nature, without disrupting the full meaning of sexual donation. In this way, the husband and wife, by respecting the full truth of their love, can adjust its expression according to such cycles, without taking anything away from the fullness of the self-donation that the union in the flesh expresses. Obviously, this requires maturity in one’s love, which is not immediate, but involves dialogue and mutual listening and a unique mastery of one’s sexual drive, in a process of growth in virtue". A message that, admitted the Pope, "many devotees will have problems understanding"; that’s why the Church "must be able to guide the couples to understand with their hearts the wonderful design that God inscribed in the human body, helping them receive what a genuine process of maturation involves".” ” ” “
