PGS mixes genes and family SES

Analyzing UK twin data, the authors show polygenic score prediction for intelligence and educational outcomes is split roughly evenly between within‑family genetic effects and between‑family effects. Socioeconomic status explains much of the between‑family portion, while height and BMI are driven mostly by within‑family genetics. Population PGS estimates for cognition thus blend individual biology with family‑level pathways. — This reframes how journalists, policymakers, and schools interpret genetic prediction in education and merit debates by showing PGS reflects both individual genes and family/SES structure.