Fetal growth and parental consanguinity.

Anthropometric measurements made on 322 newborn infants in South India were related to parental consanguinity. Uncle-niece and first-cousin marriages were common and the average coefficient of inbreeding was as high as 0·0329. The measurements (weight, length, head circumference, and triceps and subscapular skinfold thicknesses) of the uncle-niece groups (52 infants) were smaller than those of the first-cousin group (61 infants) which in turn were smaller than the nonconsanguineous group (196 infants). Statistical significance (P<0·01) was only recorded between the weights of the three groups (means 2650·4, 2794·1, and 2833·8 g) and between the lengths of the uncle-niece group and the nonconsanguineous group (means 46·92 and 47·79 cm). There were no social class or residential differences between the groups. We conclude that there are likely to be recessive genes present in the population, slightly retarding fetal growth.