Can a society embrace gay marriage and continue to ban polygamy?  Canada is in the process of finding out.  University of B.C. scholar Joseph Henrich is among the experts testifying in this British Columbia trial:

"To illustrate the harm, Henrich provides the court with an example of polygyny's cruel arithmetic.

In a hypothetical society of 20 men and 20 women, 12 men with the highest status marry 12 women. (It's always only the highest-ranking men in polygynous societies that get multiple wives.) Then, the top five take a second wife and the top two men take a third. Finally, the top guy takes a fourth. The result is that 58 per cent of the marriages are monogamous.

But -and this is the big deal -it means 40 per cent of the men remain unmarried. Yes, 40 per cent.

And Henrich's example is conservative. Blackmore has more than 20 wives. FLDS prophet Warren Jeffs, who is in jail in Utah, has more than 80. And the studies Henrich cites -from historical, frontier-American research to contemporary work done in countries where polygamy is legal -indicate that groups of unmarried men create havoc.

"For males, getting married (monogamously) is a prophylactic against engaging in crime, social disruption and other socially undesirable activities," he writes."

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His argument presumes that women will not practice polyandry, or be satisfied with same-sex marriages. . . Will the courts let him so presume? Stay tuned. . .