“we concluded that Herrnstein and Murray produced no valid evidence that genes influence within-group IQ score differences. The key evidence they cited consisted of “twins reared apart” studies and, to a lesser extent, family correlations, reared-together twin studies, and adoption studies. Aided by concepts developed in science’s ongoing “replication crisis,” we argued that the genetic findings reported in these studies do not hold up under critical examination due to environmental confounding, a reliance on uncertain or false assumptions and concepts, the use of questionable research practices (QRPs), and other problem areas. In the language of psychometrics and behavioral genetics, we argued that Herrnstein and Murray presented no valid evidence in support of above-zero IQ heritability. This conclusion, of course, automatically invalidates claims about genetic group differences.”