Why does every egg donation application ask if you are of Mediterranean ancestry?

Depends, are they JUST asking about mediterranean ancestry? Or is it ALL ethnicities? If so, then couples trying to conceive are probably looking for a donor as ethnically like themselves,most likely to keep the child from feeling out of place.But if it's only asking for mediterranean,then I have no clue,maybe the eggs of asian,african,and other ethnicities eggs are easily distinguished from each other? but other wise then, it's just the system being stupid which isn't really surprising.