Why age-of-consent laws are now distributed all over the world? What are the reasons for their development in the last century? What are the reasons for the hystery which we have seen in the last years?
It seems that there cannot be a unique answer for these questions. Reasons of such things are usually uncertain. Nonetheless, some partial answers can be given.
The most interesting contribution I have seen is the research of Killias. His thesis is that it was the separation of children and youth from adult life in the last century as the result of industrialization and the development of the school system. The point is that he was able to show such a correlation between the development of the school system and the aoc laws in the history of Switzerland's 25 cantons.