Some argue that socially, the people most disadvantaged by a polygamist society are extremely undesirable males and extremely desirable females, as a society that allows multiple women to partner to the same man leaves the men at the bottom of the totem pole without any available women.
It is interesting given Elder C’s recent comments on the socially stabilizing effect of women on society that polygamy completely undermines that effect. The most obvious is that young unestablished men have a hard time finding partners. This was a problem during the Utah period. The FLDS seem to have solved it (in an admittedly cold fashion) by kicking out young men to become “Lost Boys.”