Parental socioeconomic status (SES) is a strong predictor of children’s educational achievement (EA), with an increasing effect throughout development. Inequality in educational outcomes between children from different SES backgrounds exists in all Western countries. It has been proposed that a cause of this inequality lies in the interplay between genetic effects and SES on EA, which might depend on society and the equality of the education system. This study adopted two approaches, a classical twin design and polygenic score (PGS) approach, to address the effect of parental SES on EA in a large sample of 12-year-old Dutch twin pairs (2479 MZ and 4450 DZ twin pairs with PGSs for educational attainment available in 2335 children) from the Netherlands Twin Register (NTR). The findings of this study indicated that average EA increased with increasing parental SES. The difference in EA between boys and girls became smaller in the higher SES groups. The classical twin design analyses based on genetic covariance structure modeling pointed to lower genetic, environmental, and thus phenotypic variation in EA at higher SES. Independent from a child’s PGS, parental SES predicted EA. However, the strength of the association between PGS and EA did not depend on parental SES. In a within-family design, the twin with a higher PGS scored higher on EA than the co-twin, demonstrating that the effect of the PGS on EA was at least partly independent from parental SES. To conclude, EA depended on SES both directly and indirectly, and SES moderated the additive genetic and environmental components of EA. Adding information from PGS, in addition to parental SES, improved the prediction of children’s EA.

父母的社会经济地位（SES）是儿童教育成就（EA）的有力预测因素，并且在整个发展过程中影响越来越大。所有西方国家都存在不同社会经济背景的儿童之间教育成果的不平等。有人提出，造成这种不平等的原因在于遗传效应和SES对EA的相互作用，这可能取决于社会和教育体系的平等。本研究采用了两种方法，即经典双胞胎设计和多基因评分 (PGS) 方法，以解决父母 SES 对 EA 的影响，该研究涉及 12 岁荷兰双胞胎大样本（2479 对带 PGS 的同卵双胞胎和 4450 对异卵双胞胎）来自荷兰双胞胎登记处 (NTR) 的 2335 名儿童的受教育程度）。这项研究的结果表明，平均 EA 随着父母 SES 的增加而增加。在社会经济地位较高的群体中，男孩和女孩之间的 EA 差异变得更小。基于遗传协方差结构模型的经典双胞胎设计分析指出，在较高的 SES 下，EA 的遗传、环境和表型变异较低。独立于孩子的 PGS，父母的 SES 预测 EA。然而，PGS 和 EA 之间的关联强度并不取决于父母的 SES。在家庭内部设计中，PGS 较高的双胞胎在 EA 上的得分高于双胞胎，这表明 PGS 对 EA 的影响至少部分独立于父母的 SES。总而言之，EA 直接和间接依赖于 SES，而 SES 调节了 EA 的附加遗传和环境成分。除了父母 SES 之外，还添加来自 PGS 的信息，改进了儿童 EA 的预测。