Jeanson's Method of Inferring Past Population Sizes

[thoughtful (Valerie (non-scientist))]

@evograd

If we construct a phylogeny using the 8 modern-day (latest generation) women (men) and then apply Jeanson’s method to it (counting the number of branches through time), we would conclude that the population grew from 1 in the first generation, 2 in the second, 3 in the third, 5 in the fourth, and 8 in the fifth. But we know that the population size was constant, so Jeanson’s method leads to a completely incorrect conclusion and is therefore invalid.

If I’m understanding it right, this is perhaps just a worldview problem. Jeanson has less than 200 generations for all humanity, so there would be very few branches that get cut off - like I said, most cultures prize having at least one son, probably many more.

Evolution has a constant population size for millennia, and there would be many branches that get cut off.

Would I be correct in framing it this way?