I don't really see the point of engaging with coalburners. 100% are NPCs, you're not going to convince them of anything with a huge stack of evidence, much less a poorly articulated argument on the street. Not that just bringing up evolution is much of an argument. He should open with regression to the mean or the 95% chance she will be a single mother. Keep in mind though, race mixing is a drop in the bucket compared to other ways they suppress White birth rates.