There are rational arguments, mostly coming from evolutionary psychology and similar domains. The arguments tend to fall apart under rational scrutiny when used

There are rational arguments, mostly coming from evolutionary psychology and similar domains. The arguments tend to fall apart under rational scrutiny when used to shape human behavior rather than simply explain it. A couple recent articles by Robin Hanson about polygamy cover similar terrain in interesting ways. The arguments, particularly in the second article, more or less break it down to the problems of utilitarianism. http://www.overcomingbias.com/2010/07/polygamy-hypocrisy.html http://www.overcomingbias.com/2010/07/polygamy-hypocrisy.htm... http://www.overcomingbias.com/2010/07/hypergamy-and-polygamy.html http://www.overcomingbias.com/2010/07/hypergamy-and-polygamy...