Hilger argues that racism does play an important role in explaining Black-white wage differentials but it’s the historical racism that made black parents less skilled and less able to pass on skills to their children. In the twentieth century, Asians, Hilger argues, were discriminated against in the United States at least much as Black Americans. But the Asians that came to the United States had high skills while the legacy of slavery meant that Black Americans began with low skills. Asians, therefore, were better able to overcome discrimination. The success of Nigerians and Jamaican immigrants in the United States also speaks to this point. (Long time readers may recall that in 2016 I dubbed Hilger’s paper on Asian Americans and Black Americans the Politically Incorrect Paper of the Year .)
The implied causal link in the graph above is from the mom's high school education ==> child's education ==> income.
As you can see there is an effect but it is almost all from the mother going from having less than a high school education to graduating high school (11 to 12 years). In contrast, the mother can move from graduating high school to having a PhD and there is very little change in the education level of an adoptee.