# Developmental Origins of Disease (Barker Hypothesis)

Prenatal conditions can alter adult disease risk, but the effect depends on the exposure, developmental window and later environment; low birthweight alone does not prove fetal nutritional programming.

The registered primary SC3 yields Ε: defined prenatal exposures have human causal support, while internal and external negatives map limits to generalization. SC1 retains Β and controlled developmental SC2 retains Ε. This judgment uses an explicit closest-rubric adaptation because the literal aging-specific requirement is inapplicable to the developmental claim. The absence of a human deprivation RCT does not itself cap valid natural experiments; independence and specificity, rather than an observational label alone, block Ζ at the broad exposure class.

Boundaries are measurable gestational window, sex, species/strain, defined drug/nutrient exposure, social/geographic setting and postnatal environment. Nulls are retained rather than retrospectively excluding nonresponders. A risk contribution is not universal necessity, immutability or a prediction that every exposed person becomes ill.