The restrictions on birth control were primarily a survival plan. The more people in our 'gang' the safer we are. Same for ensuring by that the children brought about by the lack of contraception remain part of that gang. No need for it nowadays but sadly old habits die hard :-( I may get in lumber for this but I see the dress styles of orthodox Muslims as a similar ploy. The more people can see how many Muslims there are the safer they will feel and the more annoyed the bigots become. Those old blokes in frocks must be rubbing their hands in glee and sadly many still fall for it!