The following article from the Globe and Mail, written by Marina Adshade (economist at Dalhousie University) makes an interesting arguement for decriminalization:
The overwhelming majority of Canadians do not want to live in a polygamous household and, from an economic perspective, that observation is a bit of a mystery.
For a country like Canada, in which wealth is very unequally distributed,economic theory predicts that wealthy men should have more of everything, including wives. This doesn’t suggest that wives are property. It suggests that if income matters then women who are maximizing their welfare, and the welfare of their children, should prefer to be the second, third, fourth wife of a very wealthy man to being the only wife of a poor man. Yet, despite high levels of inequality, the industrialized nations of the world all have adopted monogamy as the dominant marriage institution.
The explanation for why monogamy is preferred has to do with the way in which personal wealth is generated in industrialized nations.
In industrialized nations wealth is generated by those who are highly skilled. There is an economic argument for having only one spouse in an economy where wealth is a function of education – better educated men want to have better educated children and the best way to do that is for those children to have a well educated mother. Educated women have more bargaining power in the household and are better equipped to negotiate an arrangement where they are the only wife. Less educated women marry less educated men, but those men can only afford one wife anyway, and so monogamy pervades.
In Canada we don’t have monogamy because the laws enforce this marital arrangement, we have these laws because historically this has been the arrangement that the majority has preferred.
So the question is, if monogamy is the best arrangement for those who can afford additional spouses, why does this institution need to be enshrined in the law? In the economic sense a policy is not optimal if someone can be made better off without making others worse off. If this is the criterion, then it has to be that criminalization of polygamy not be an optimal policy. If we allow everyone to act in their own best interests when making marriage choices, and assume that parents act in the best interest of their children, then surely those who chose to live in a polygamous household are better off than they would be in a monogamous household. They have to be because that is the arrangement they have chosen.
You can’t make someone better off by forcing them to choose an alternative form of marriage that they do not prefer.
You may be worried that someone is being made worse off – the poor guys who can’t find a wife because some men are taking more than their share. But, there will never be so much polygamy in Canada that it will add to the pool of men who will never marry.
Anyhow, the fact that so many women prefer to remain single than to be married to man who they don’t desire as a husband is a much bigger contributor to bachelorhood than polygamy ever will be.
Merrywives' Blog 
Chris, though you cited the flioowlng to suggest that Kinsey’s 10 percent has been taken out of context Nonetheless, what Kinsey did claim was: The study also reported that 10% of American males surveyed were more or less exclusively homosexual for at least three years between the ages of 16 and 55 To me, that suggests something even more radical than the notion that 10 percent of the population is gay it suggests that people can have gay sex or gay relationships exclusively for at least three years, and then go back to having straight sex/relationships. That’s a much more radical notion of the fluidity of human sexuality, outside of prison, than the mere idea that 10 percent of the population is born gay.A number of studies behind my original link were specifically designed to correct for the alleged biases of Kinsey’s original study. than 1 or 2 percent.Chris and Jesse, I’m not surprised that you’re surprised by the notion that homosexuality and homosexual behavior are more prevalent then you thought. Unless you’re gay and out yourselves, every gay or bisexual person you’ve ever met in your life was either diligently or casually hiding that fact from you, discreetly not mentioning it because it either seemed irrelevant or possibly a source of tension, answering a direct question with courageous honesty, or stating it outright to you to make a point. In other words, particularly if you’re not gay, the world is designed to hide gayness from you in a million little ways particularly the incidence of gay feelings and gay sex among people who generally identify as straight.There are many non-Asian San Francisco residents who are shocked to learn that the city’s population is at least 30 percent Asian. After all, they say, my neighborhood doesn’t have very many Asian residents, I don’t have any Asian friends In such a case, the sample bias is obvious. But imagine if people could hide their ethnic backgrounds to get past racist barriers and assumptions that 30 percent figure would seem even more shocking to many whites.But yeah, Jesse I have the same experience as you with porn. It just wasn’t around when I was growing up, other than Playboy and those shops in areas downtown I never went to.