Not sure if polymath is on this forum, but I know a lot of guys object to polygamy on the basis that some men will have to go without wives. That just isn't true. So I made a simulation, and ran it with various parameters for 1000 years at a time. The results were interesting, but in every case, even in the extreme situation that every man had 2 wives, there was no shortage of women. Even though the male birth rate was 5% higher than the female birth rate. How is this sleight of hand performed? It has to do with the time element. When you have a system of many interacting particles, it can be hard to predict how they will act over time. Like with Chaos research, only putting in the parameters and letting the system run, will tell you what it will do. Oh, and the details: on average, men got married at age 40. But it was to young women, not women their age. Source code available if anyone wants to run the simulation themselves, tweak different parameters, and see which factors are the most important. Code: (define maxwives 2) (define male-age-of-death 72) (define female-age-of-death 79) (define male-age-of-majority 18) (define female-age-of-majority 16) (define female-age-of-menopause 42) (define female-age-of-widowhood 60) (define male-birth-ratio (div (add 1 1.05))) (define average-number-of-children-per-woman 2.7) female-age-of-widowhood is the age after which a women doesn't remarry if her husband dies. I took this from the Bible; after age 60, the congregation supports the widows, but before that age they are expected to remarry. The simulation made some simplifying assumptions, as for an ideal world. Everyone lives a full lifespan; no premature death. Marriage is until death; noone ever feels a need for divorce. There are no out-of-wedlock births; all sex and births are within a marriage. I could add those things in, but even in its simple state, the complex behavior of the system is interesting to watch. Population demographics aren't easy to predict, and not possible to model with calculus and linear equations.