This volume constitutes probably the most comprehensive report on inbreeding effects in man. The study first began to take shape in 1955, so this report covers the work of approximately ten years. Schull and Neel have collaborated with many Japanese medical scientists and statisticians.
The material is organized into 15 chapters. The first gives the general background. The second describes the situation of consanguineous marriages in Japan. The third outlines the statistical methods employed in the analysis. This is then followed by ten "data chapters" on the characteristics of the consanguinity group, mortality of the inbred infants and children, medical histories, physical disease, anthropometrics, growth and development, dental characteristics, laboratory studies, neuromuscular and mental status, and performance in elementary school. The 14th chapter summarizes the differences between an average inbred and an outbred child. The final chapter discusses the relationship of the inbreeding results with the so-called "genetic load."