Sex

Medieval Mating Patterns
Europe is the largest landmass furthest from the equator where one can still reasonably do subsistence farming. This however left early European peoples with little access to Vitamin D, since the crops could not provide it - they had to hunt for it, or synthesize it themselves by spending more time in the sun, with less clothing, which was quite difficult to do in the sunlight-starved latitudes of Europe.

This chronic deficiency in Vitamin D leads to severe depression and depressed immune systems. The weak vitality of Europine peoples due to the climate and nutrition meant that conception was often difficult. Premarital sex was encouraged, with weddings soon following after a successful pregnancy was showing.