No I mean, the mixed kids scored similar to white kids. A bit lower. But some of them looked black and didn't know one of their parents were white. If the reason black people scored lower was because of systemic discrimination as opposed to being genetic, then you would expect the mixed kids to score similarly to black people, if they and the society thought the mixed kids were black. But that didn't happen. The mixed kids scored better than black people irrespective of adoption background and irrespective of whether they and the society around them thought they were black.
That's my takeaway.