At least one of every five marriages is consanguineous (between couples who are second cousins or closer) in the Middle East and North Africa, and the rate is higher than 50 percent in some parts of the world. Consanguineous marriage generates serious health problems for the offspring and...

Powerful currents have reshaped the structure of families over the last century. There has been (i) a dramatic drop in fertility and greater parental investment in children; (ii) a rise in married female labor-force participation; (iii) a significant decline in marriage and a rise in divorce; (iv)...