you are referring to "between humans" right? cuz our cattle are kinda sexually liberal, dogs, cats.. etc... in fact most of the animal kingdom is okay with whatever... so humans?
Yes humans. Last I checked we don't do legal marriages between animals in the USA.
hey im just checkin'... i watch a good deal of fox news and i hear polygamy is a gateway drug to bestiality and a myriad of other krazy sex stuff i don't want people to do....