Is birth weight determined genetically?

Abstract

Birthweight correlations were analysed among 505 intergenerational pairs of first births to women aged 18-25 identified from a large obstetric data bank. After standardisation for fetal sex, maternal height, gestational age, and proteinuric pre-eclampsia residual correlations of between 0.1402 and 0.1725 were found, suggesting only a small genetic effect. It is concluded that genetic factors play only a small part in determining birth weight.