"Another very grave danger is that naturalism which nowadays invades the field of education in that most delicate matter of purity of morals. Far too common is the error of those who with dangerous assurance and under an ugly term propagate a so-called sex-education, falsely imagining they can forearm youths against the dangers of sensuality by means purely natural, such as a foolhardy initiation and precautionary instruction for all indiscriminately, even in public; and, worse still, by exposing them at an early age to the occasions, in order to accustom them, so it is argued, and as it were to harden them against such dangers. Such persons grievously err in refusing to recognize the inborn weakness of human nature, and the law of which the Apostle speaks, fighting against the law of the mind; and also in ignoring the experience of facts, from which it is clear that, particularly in young people, evil practices are the effect not so much of ignorance of intellect as of weakness of a will exposed to dangerous occasions, and unsupported by the means of grace. ... False also and harmful to Christian education is the so-called method of 'coeducation.' This too, by many of its supporters, is founded upon naturalism and the denial of original sin; but by all, upon a deplorable confusion of ideas that mistakes a leveling promiscuity and equality, for the legitimate association of the sexes. The Creator has ordained and disposed perfect union of the sexes only in matrimony, and, with varying degrees of contact, in the family and in society. Besides there is not in nature itself, which fashions the two quite different in organism, in temperament, in abilities, anything to suggest that there can be or ought to be promiscuity, and much less equality, in the training of the two sexes. These, in keeping with the wonderful designs of the Creator, are destined to complement each other in the family and in society, precisely because of their differences, which therefore ought to be maintained and encouraged during their years of formation, with the necessary distinction and corresponding separation, according to age and circumstances. These principles, with due regard to time and place, must, in accordance with Christian prudence, be applied to all schools, particularly in the most delicate and decisive period of formation, that, namely, of adolescence; and in gymnastic exercises and deportment, special care must be had of Christian modesty in young women and girls, which is so gravely impaired by any kind of exhibition in public.”
