Has there been any survey to figure out why is it like that? I think that it does not hurt and ask the questions from sizeable enough population sample to make

Has there been any survey to figure out why is it like that? I think that it does not hurt and ask the questions from sizeable enough population sample to make some conclusions. Or is it avoided by some reason? I know that Catholic Church has a lot of influence over South America, can this be related to this? I think that it is actually very important to every individual on Earth to figure this out as more we have people on Earth the less can be shared among us and is there space for other species.