121 All these admonitions which have been renewed and confirmed by Our solemn authority must likewise be applied to a certain new kind of socialist activity, hitherto little known but now carried on among many socialist groups. It devotes itself above all to the training of the mind and character. Under the guise of affection it tries in particular to attract children of tender age and win them to itself, although it also embraces the whole population in its scope in order finally to produce true socialists who would shape human society to the tenets of Socialism.
Source: Quadragesimo Anno (Vatican.va)