Flying Crane
Sr. Grandmaster
First, please give me an example of the cancer you are thinking of, so we can begin on the same page.As I wrote before without going into details. There are certain types of cancer that a particular "race" (call it what you want, it's just semantics) is MUCH more susceptible to. There is no two ways around this and no amount of social science extrapolations can circumvent it. If this does not satisfy a race distinction, then I don't know what does.
Second, there can be distinctive genetics within ethnic populations, but that too is not absolute. There are gradations, there is no way to draw a clear line geographically where these distinctions within the population begin and end. People intermingle and intermarry and have children and mix all that up. Nothing about this supports the identity of three “races” one of which has larger and more durable joints than the rest. That is what I was commenting on.
Variations within and between ethnic groups? Of course there are.