Ooops, soren1, I do apologize, I see your source now. It was important and I missed it. And it brings up a lot of questions about the practice of polygamy that are difficult to answer with regard to fertility and married/unmarried partners. I am thinking that there are less unmarried woman under polygamy but I don’t know for sure. Any sources on that?
In this particular study, it was found that each additional wife in a polygamous family decreased the lifetime fertility of the other wives by one child each. Do you realize how drastic that is? It is a devastating blow that destines polygamy to become counterproductive once the number of wives exceeds a certain, small number. Specifically, if a monogamous wife has X children, then plural marriage will become counterproductive when the male exceed X/2 wives. Let’s take a mild case to see what this pattern predicts. Let’s say a man has just two wives. What is the impact of that on their fertility? Suppose the expectation for a monogamous woman born in a given year is to have seven children. If she marries a man with one other wife, so that each wife is now expected to produce six children, we already have a big drop, of a full 14%, for female fertility. With a third wife, the drop attains to 28%.
To offset a reduction of that magnitude by creating more opportunity for women to marry would require a high excess of women in the Utah territory, thought there was none. At its zenith, 17% of Mormon men were polygamous. If we take the most conservative estimate that mathematics allows, and say that each had only two wives, and that the female population was exactly equal instead of smaller than the male population, we can calculate that 34% of women belonged to polygamous unions. A 14% drop in fertility among those women would therefore amount to a 5.8% reduction in reproduction among the entire female population. Business would have to be really booming for the other women to offset that kind of loss. It would require polygamy to yield a major improvement on male availability to women. Yet, because, as in all frontier states, men already outnumbered women in Utah by a fair margin, then the increase of unmarried males was mostly water over the dam. There were already excess men available to the women. That will not make the kind of impact that could overcome a near-6% drop in reproduction.
Remembering of course that 6% is a number I predict from the most conservative initial estimates, the gravity of the situation appears even more clearly if you know the real number that the study found. I just read it, and it says that the mean drop in reproductive success among Mormon women over a sixty-five year period was a full 37%.
The study you cite is on 19th century Mormons. I’d be interested if modern Muslims show the same effect. Polygamy there is much more acceptable and has been practised for much longer. I think you’d probably get more reliable results.
I cited a study on nineteenth century Mormons, because those are the people who are relevant to our discussion. Yet all of the reasoning I gave for why the study’s results are predictable should apply to polygamy generally. The question I put forward, to which you have yet to venture an answer, is pretty much culturally neutral: * Is a woman going to have as many children when her husband shares his attention with three other women as when he is devoted only to her?*
I can easily believe that the adverse effects of polygamy on birth rates might differ
in degree from culture to culture. Might there be some society where the impact of having a new wife reduces the fertility of the others by only .5 children each? Maybe. But there is no reason to suppose that polygamy could actually help, and the data has only confirmed what was already obvious, and was certainly obvious to me long before I ever read about the research. All it would take for polygamy to reduce the birthrate would be if this happened from time to time:
A woman, because her husband spends time with his other wife, occasionally conceives one month later that she would have if he had been with her during her previous period of fertility. That’s it. That little delay, even if only occasional, ensures the conclusion. Repeated over time across any polygamous population, it would lower the birth rate perforce. Or do you think that only happens in Utah?
But don’t let the open-and-shut statistical arguments distract us from my original point. The reason I am arguing about the adverse effects of polygamy upon procreation is not sociological, but theological. This is because it disproves the only theological justification Mormons have for why God can authorize polygamy:
For if I will, saith the Lord of Hosts, raise up seed unto me, I will command my people; otherwise they shall hearken unto these things. (Jacob 2:30)
When polygamy is revealed to be
A) a formula for slowing population growth, and
B) an historic cause of stagnation in growing the LDS population, then we can see both that Jacob’s words here are false in their own right and also inapplicable to Mormons historically. At the same time, Jacob’s main objection to polygamy, the suffering of women under their husbands and the value of chastity were compromised under Mormon polygamy.
