Even when the mariages are between adults, if the community if polygamist, then the girls tend to be traded like cattle and low-status young men create problems for all. This is true across time and culture.
History suggests that it is. A new study out of the University of British Columbia documents how societies have systematically evolved away from polygamy because of the social problems it causes. Women are usually thought of as the primary victims of polygynous marriages, but as cultural anthropologist Joe Henrich documents, the institution also causes problems for the young, low-status males denied wives by older, wealthy men who have hoarded all the women. And those young men create problems for everybody.
For more on this, read my review of
God’s Brothel: The extortion of sex for salvation in contemporary Mormon and Christian fundamentalist polygamy and the stories of 18 women who escaped