How tribalistic polygamy rots the gene pool

There are a lot of arguments against polygamy from a spiritual, moral and philosophical perspective. But is there also solid scientific evidence that polygamy is bad for the species?
There’s no question that over the past tens of thousands of years of human history, polygamy has left a mark on the human genome that may indicate that small numbers of males must have mated with large numbers of females.

Over time, this polygamous pattern will spawn more genetic differences on the X chromosome than it will on all of the other human chromosomes. That’s because women naturally have two copies of the X chromosome while men have only on X chromosome and one Y chromosome.
To put it another way, diversity arises because some men don’t get to pass on their genes while most women do.
Evidence of Polygamy in Human DNA
The evidence of polygamy among early humans can still be seen in our genes.
“Humans are considered to be mildly polygynous and we descent from primates that are polygynous,” Hammer said.
The term “polygyny” refers to the practice of males mating with multiple females. Among humans, it’s takes the form of polygamy or multiple marriages.

Even if people in the West don’t take multiple wives at the same time, men tend to father children with more females than females do with males. This is a practice known in the scientific community as “effective polygamy”.
But is it good for the gene pool?

Systemic polygamy Is Bad for Genetics and Society
But is it good for the gene pool? Perhaps not.
Not only is polygamy eroding the human DNA genome, it’s rotting away our culture as well.
Polygamy tends to create a multi-tiered society: Those men with power and money can take multiple wives. This puts them into a higher social class while men who can’t afford multiple wives – or even one wife – are assigned a lower social value.
When men don’t feel valued by society, inevitably this leads to an increase in risk-taking, resulting in even more socially undesirable behaviors, as well as the consequent increased cost of additional policing, private security, and government-sponsored national defense expenses.
Faced with the prospect of high competition with other males for the attention of fewer females and with little chance of obtaining even a single wife, men without mate can feel as if they have little to live for, which quickly leads to an erosion of personal values.
The resulting breakdown in societal order could be catastrophic and can include such direct consequences as a higher murder rate, an increase in violent crime, higher incidences of rape and kidnapping of women, prostitution, human trafficking, and property crimes.
Drug and alcohol abuse is also more prevalent among single, unmarried men – especially those with no hope of finding marriage anytime in the future – which further accelerates the breakdown of social order.
The bottom line is that polygamy is not only bad for human genetics, but human society as well.