Make polygamy law give additional population growth

[humble nimbus]

Not really, the number and proportion of women who are childbearing will be the same, and any advantage is wiped out by all the male-on-male violence

[dusk flax]

i mean, to this day muslim families are pretty big

one of the reasons is more wives

[humble nimbus]

Individual family size doesn't matter for pops

The number of women is the same

The number of childbearing women is what determines population growth

Doesn't matter if 2 women have 4 children each if they share one husband or have one each

[deep sundial]

This isn’t true. In most majority-Muslim countries the practice is considered, functionally or in some cases through Islamic Jurisprudence, to be mukrah - that is, allowable but for the most part discouraged. In Indonesia, by far the most populous majority-Muslim country, about one percent of all households were polygynous. The standout exceptions are Aftican nations, but many cultures and groups outside of Muslims practice polygamy there, and some few even do polyandry; even in that context, the number of people in polygamous households is well below half.

The traditional position of jurisprudence has been that multiple wives may only be taken if you can treat all of them fairly financially and emotionally. This has generally excluded most men even among the most successful members of society, and while we may scoff at the notion there’s ample evidence that suggests most Muslims in the ancient world took this consideration very seriously by the time period of the game. Sultans and nobles and other very wealthy people did have harems, but it very much wasn’t the norm for most families, whether for logistical, social or religious reasons.

[compact moss]

yeah but family size doesn't matter, there are fewer families since more of the wives are in the same family if that makes sense. The only thing that dictates population growth in a country is children per woman, and nothing about having multiple wives increases this