(48) The problem of de facto unions constitutes a real challenge for Christians in their ability to demonstrate the rational aspect of the faith, the profound rationality of the Gospel of marriage and the family.  A proclamation of the Gospel without this challenge to rationality (in the sense of an intimate correspondence between man’s desiderium naturale and the Gospel proclaimed by the Church) would be ineffective.  For this reason, today more than in other eras, it is necessary to make known in believable terms the inner credibility of the truth about man which is at the basis of the institution of conjugal love.  Different from what occurs with the other sacraments, marriage also pertains to the economy of Creation and is inscribed in the natural dynamics of humankind.  Secondly, a renewed reflection is also necessary on the fundamental bases, the essential principles that inspire educational activities in the different milieus and institutions.  What is the philosophy today of the educational institutions in the Church, and what is the way in which these principles flow into an appropriate education to marriage and the family as both fundamental and necessary nuclear structures for society itself?