Why is it 2.1 births per woman to sustain population levels?

Question

Why isnt it just 2? What factors make up the 0.1?

In: Other

Answer 1

.1 is to make up for deaths.

So 2 replicates the mother and father, and .1 hedges against deaths that take place in children, those who are sterile, etc.

If you want to grow your population, 3 is a better number. There’s more losses than .1 covers for sustainability.