Within‑family Scores Predict Cognitive Ability

Using sibling comparisons in two cohorts (UK Biobank, N≈4,642 sibling pairs; ABCD, N≈736 pairs), researchers show that most of the predictive power of cognitive polygenic scores persists within families (within‑family attenuation ≈0.88), and after correcting for measurement error the within‑family association with latent general ability is ~0.45. The score also retains about 66% of its effect in African‑ancestry samples and predicts education, occupational status, and lower cardiometabolic risk. — If robust, these findings change the evidentiary basis for policy and ethical debates about education, screening, insurance, reproductive technology, and how genetic predictions should be used or regulated.