Throughout these articles the use of ‘inherited DNA differences’ and ‘genetic propensities’ can be understood in terms of the following: According to Robert Plomin, “The ability to measure inherited DNA differences directly has led to polygenic scores and to new methods to estimate heritability and genetic correlations.”²

A polygenic score is constructed by “using inherited DNA differences to predict, from birth, common disorders and complex traits.”³⁶¹ Aggregated across the genome, that index is then interpreted as a person’s “genetic propensity or likeliness to think, feel, and behave in certain ways.”³⁶³