Why is this frowned upon?
Saying it is illegal and morally wrong isn't a valid argument since it could be argued that our views on right and wrong are also (but not limited to) based on what is legal or not. Homosexuality is illegal in some countries but many would blame the law, not the moral position, as being wrong.
Personally, while I'm supposed to accept polygyny as a Muslim (you know who the father is...but with DNA testing maybe this Islamic legal aspect could be reformed...), but using the argument that as long as it doesn't hurt others what people do is their matter then there doesn't seem to be a problem with polygamy.
So, should society be more receptive to polygamous relationships? Do people here think it's wrong?