The big issue here is that the reasoning behind outlawing polygamy is flawed. Polygamy is illegal because, essentially, people find it morally abhorrent or unnatural.Some people do invoke Discredited Arguments 4 and 5.
From a biological perspective, our commitment to monogamy as a species is questionable. Out of the roughly 5,000 species of mammal, only three to five percent are monogamous - and of those, most commit so intensely to their partner that they will not mate again even if their mate is killed. The human commitment to monogamy is nowhere near as serious, as evidenced by the number of people who remarry after divorce or a spouse's death.Very few people have only one spouse or partner over their lifetime.
Yet in the United States, monogamy is enforced by law with criminal adultery statutes, laws against bigamy and child custody laws. While prosecutions pertaining to violations of these laws are rare, statutory penalties against these crimes range from two years' imprisonment to commitment for treatment of insanity.Bigamy should only be a crime if done as a fraud. Having multiple spouses who have agreed to the situation should not be a crime. It should be legalized. There is no good reason to deny that an adult, regardless of orientation, gender, race, or religion, should be free to share love, sex, residence, and marriage (and any of those without the others) with any and all consenting adults, without prosecution, bullying, or discrimination. Let's keep the momentum going.
The writer make several references to the same-gender freedom to marry and cites an opinion from a gay writer. It is important to note that, just like everyone else, there are LGBT people who are polyamorous or polygamous, some who aren't but support the polygamous freedom to marry, and some who are against the polygamous freedom to marry.
Lies and Damned Lies About Polygamy