J.G. Engelmann, "Decreasing Fecundity," Philadelphia Medical Journal, January 18, 1902.

It has, further, been frequently denied that Neo-Malthusian practices can affect Roman Catholic countries, since the Church is precluded from approving of them. That is true. But it is also true that, as Lagneau long since pointed out, the Protestants of Europe have increased at more than double the annual rate of the Catholics, though this relationship has now ceased to be exact. Dumont states (Dépopulation et Civilisation, chap. XVIII) that there is not the slightest reason to suppose that (apart from the question of poverty) the faithful have more children than the irreligious; moreover, in dealing with its more educated members, it is not the policy of the Church to make indiscreet inquiries (see Havelock Ellis, Studies in the Psychology of Sex, Vol. VI, "Sex in Relation to Society," p. 590). A Catholic bishop is reported to have warned his clergy against referring in their Lent sermons to the voluntary restriction of conception, remarking that an excess of rigour in this matter would cause the Church to lose half her flock. The fall in the birth-rate is as marked in Catholic as in Protestant countries; the Catholic communities in which this is not the case are few, and placed in exceptional circumstances. It must be remembered, moreover, that the Church enjoins celibacy on its clergy, and that celibacy is practically a Malthusian method.