Question from a reader:
Marriage between one man and many women is very prevalent in the Bible, but these days “Biblical Marriage” is virtually always represented as between one man and one woman. I haven’t gone looking for any research to support this, but I 
suspect that a comparison of parenting outcomes from polygamist households would show better than average results. If following the Bible and providing an excellent environment for the rearing of children is your intent, it seems as if you should be more supportive of polygamy.
What the bigot has to say:
One of the great assets of the Bible is that it does not sanitize real life. It’s patriarchs, kings and prophets (like all of us) have moments of greatness and moments of great failure. This feature is one of the primary reasons why atheist CS Lewis (expert on allegory, myth, and literature) began to investigate Christianity. He observed that unlike myth and many religious texts, the heroes within biblical stories were uncommonly flawed. The writers of the gospels, for example, were strikingly self-effacing.
Within scripture there are prescriptions (what God says we ought to do) and descriptions (stories of real life which may or may not include commentary). The bible describes people transgressing God’s standard in every generation and in every way, usually when imitating the surrounding cultures- cheating the poor, offering their children as a sacrifice, mimicking pagan worship practices, engaging in polygamous marriages, etc. For those in scripture who did choose to engage in polygamy, the Bible is detailed about the household fall-out that ensued. But when the Bible prescribes standards for marriage, it is between one man and one woman. There is no prescription for polygamy.
I have not examined how children fare when being raised within a polygamous environment. But I heard a piece on NPR where leading polygamous figures conceded that the fight to legalize polygamy is about 20 years behind the same-sex marriage battle. So it may not be long before that familial structure is being scrutinized as well.
askthe"Bigot" 
How long before the left/liberal crowd decides monogamy is “racist” and must be stamped-out? (You know it’s coming.)
“Meanwhile, organizations advocating for the legal redefinition of marriage label themselves as being for “human rights” and against “hate.” The implications are clear: if marriage is legally redefined, believeing what every human society once believed about marriage- namely that it is a male-female union- will increasingly be regarded as evidence of moral insanity, malice, prejudice, injustice, and hatred.”
From “What is Marriage” Harvard Journal of Law & Public Policy, Vol. 34, No. 1. P 20