Why Monogamy?

One wonders why major religions at least one in particular Christiantity has upheld chastity in marriage for both men and women as a moral obligation. Why the seemingly irrational disdain for sex and sexuality, well it turns out there is a good reason, and that reason is because it results in better moral outcomes particularly when it comes to the rate of crime in society. This is stated in a study in the University of British Columbia.

J. Henrich, R. Boyd, P. J. Richerson. The puzzle of monogamous marriage. Philosophical Transactions of the Royal Society B: Biological Sciences, 2012; 367

Link: 10.1098/rstb.2011.0290

Abstract:

The anthropological record indicates that approximately 85 per cent of human societies have permitted men to have more than one wife (polygynous marriage), and both empirical and evolutionary considerations suggest that large absolute differences in wealth should favour more polygynous marriages. Yet, monogamous marriage has spread across Europe, and more recently across the globe, even as absolute wealth differences have expanded. Here, we develop and explore the hypothesis that the norms and institutions that compose the modern package of monogamous marriage have been favoured by cultural evolution because of their group-beneficial effects—promoting success in inter-group competition. In suppressing intrasexual competition and reducing the size of the pool of unmarried men, normative monogamy reduces crime rates, including rape, murder, assault, robbery and fraud, as well as decreasing personal abuses. By assuaging the competition for younger brides, normative monogamy decreases (i) the spousal age gap, (ii) fertility, and (iii) gender inequality. By shifting male efforts from seeking wives to paternal investment, normative monogamy increases savings, child investment and economic productivity. By increasing the relatedness within households, normative monogamy reduces intra-household conflict, leading to lower rates of child neglect, abuse, accidental death and homicide. These predictions are tested using converging lines of evidence from across the human sciences.


In fact this study is not very controvestial at all, among ethologists whom study animal behaviour this phenomenon is the norm, this isn't based itself in evopsych but in concrete observations of how animals behave. You can learn more about the difference ofwhat makes a particular animal species a monogamous one and what makes it polygamous by watching a Lecture series presented by Dr. Robert Sapolsky on Human Behavior, one well worth watching. Link provided below starts at the appropriate time at about and 1hr and 18mins.

Explanation of Behavioral and Anatomical Differences of Monogamous and Polygamous Species