Referring to this article, and recent divorces as a consequence of infidelity, my friend asked,

Would knowledge that there was a genetic component in polyamory make a difference? Would it make us more tolerant? Would it make it easier to accept?

My response:

The article is full of speculation, based on the author’s “personal experience” and his conclusions about what must “surely” be true “in the margins.” However, his point in opening the reader’s mind to various possibilities is to conclude that all choices should be respected as long as people “love each other, treat each other with respect, and live happy, productive lives.” I’ll come back to this shortly.

The existence of identical twins who differ in sexual orientation has proven that it is not genetically determined. This does not mean we can conclude that it is a “lifestyle choice.” It can be biological and independent of rational, intentional choice without being genetic. Call it “sub-rational.”

As far as there being a biological or sub-rational “component in polyamory,” I for one have long figured there is! Females, by definition, must invest orders of magnitude more resources into reproduction as compared to males. Hence, males derive advantage from spreading their genes among multiple partners (a diversification strategy). There is an indirect motivation for females, who derive advantage from collecting resources from multiple partners (a concentration strategy). Such biological economics are interedpendent with genetic traits.

As far as acceptance of polyamory is concerned, throughout global history, polygyny and even polyandry has been accepted and even institutionalized. I don’t think the same can be said for same-sex marriage, at least not to the same degree.

So, it’s not clear that knowledge of a genetic component would make polyamory more acceptable.

The reason it makes marriages fall apart is because in modern America, marriage is by social and legal definition, monogamous. We modern Americans tend to put trust and faith in the monogamy. Therefore, to engage in polyamory while married is, in most cases, a violation of a social pact and a betrayal of trust. It breaks the “treat each other with respect” part of the author’s conclusion.

I say “in most cases” because (though I have zero direct experience of this) there are marriages of convenience and open marriages where the partners, at least, have a clear mutual understanding of the terms. However, because modern American society does not accept these, the partners, their friends, and their children may still suffer social stigma or displacement.