PS: this topic also tends to just naturally lead to questions about what it means to be a different "race" from other humans of other races.

It's a fair question. Nothing wrong with asking, since it's a term that is used all the time in society and by governments and police.

Traditionally, we have tended to define this term "race" based upon primarily skin tone (so the amount of melanin in your skin).

BUT, the interesting thing is:

There is far more DNA involved in coding for blood type, than how much melanin you have in your skin.

So that means, if someone insists upon rigidly dividing humans into "race" (which doesn't really make much sense according to DNA science, but whatever...), then...

If someone insists upon doing that, and dividing us all into "races" then it makes FAR MORE sense to divide humans into racial categories based upon blood type!

Rather than how much melanin they have in their skin.

Again, that's because there is much more complex DNA coding involved in determining blood type, than melanin in skin.

In fact... people with the same blood type are so much more genetically identical to each other, that they can literally SHARE BLOOD with each other in emergencies, and be just fine!

Whereas, usually, when it comes to someone in your own "race" who has a different blood type than you... you two are sufficiently genetically different that your blood would be POISON to each other.

And so you can't share blood, not even if they are in the same "race" as you, in that scenario. (Putting aside the topic of universal donors.)