[AndrewC]

From an evolutionary standpoint, better for a fraction of the population to be seriously anemic than for the whole population to be dead of malaria. But you know this.

And you know that malaria is not 100% fatal to non-carriers.

[general_re]

Carrying isn't a guarantee of survival either, but your odds are greatly improved:

"Protective effects of the sickle cell gene against malaria morbidity and mortality."

[shubi]

He did overstate it, but malaria provides more negative pressure on reaching breeding age than sickle cell.

Biology doesn't care about people reaching into old age, just giving them the best opportunity to reproduce and raise young.

This results in sickle cell being more prevalent in malarial areas than clear areas. It is why blacks have more sickle cell than other races, even when out of danger for hundreds of years.