I understand that many women will not have kids or will have only one kid, or that child mortality is involved but still a fertility rate of 2 means that ON AVERAGE every woman will have 2 kids. This means that every woman and man will be replaced, including the children that die young if the rate of 2 lasts (the newborn females will also have on average two kids). So why isn’t a fertility rate of 2 enough to replace the population?
In: 701
Another nuance that I haven’t seen anybody mention yet.
So I ran a simulation for a population growing for something else and got perterbed when my population kept collapsing with a replacement rate of 2 and nobody dying before reaching reproductive age.
What I realized is it you average 2 children exactly then not exactly half will be male and female. Ignore that more males are born and we assume 50% chance just through random deviation you’ll either have more males or females way time.
If they pair up and average 2 children then there will be some single people of the majority sex who cannot find a mate.
503 makes, 497 females means only 497 reproducing couples in my simulation. So I needed a number just shortly greater than 2, wasn’t exactly 2.1 but close and then it stayed roughly stable.
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