While doing a literature review for a paper about syphilis, I learned that Sweden has had what we would now call comprehensive sex education since 1918 ("Venereal Diseases and Sex Education", Report by a Swedish Government Committee, British Medical Journal, vol 1, no. 3204, May 27, 1922, p.842), as part of their "venereal disease" prevention law.
A 1943 discussion of sex education shows that current discussions are almost identical to past dicussions. The Archbishop of Canterbury noted that "if men and women would abstain from fornication the problem would be reduced greatly and become a purely medical matter. The bulk of the evil is primarily a moral problem." and he suggested that by distributing condoms to the troops "the implication is that many are expected to practice fornication" and thus it increases. One person cited one example in which moral suasion worked to prevent sex among soldiers --- the Black Sea Army in World War I --- and that the forces would respond if chastity were portrayed "in the right way".
On the other side, a medical officer from St. Pancras argued that the Church's teaching was unhelpful and that creating a taboo against premarital sex causes those who break the taboo to become rebels and outcasts. An alderman calls for sex education for those age 13 and up since otherwise they will learn about sex from "street talk", while a doctor calls for sex ed starting at age 11. Meanwhile, a minister in the Church said that he has discussed venereal diseases openly for years, and in a separate report, a psychiatrist noted that "The clergy were more broad-minded than schoolmasters."