ABSTRACT
Most Americans endorse the ideal of equal opportunity, and many interpret this ideal as requiring that children from different backgrounds have an equal chance of achieving economic success. Most Americans also recognize that children whose parents have "all the advantages" are more likely to prosper than children whose parents lack these advantages. A growing body of evidence suggests that genetic differences can influence an individual's earnings. Economists use the term "human capital" to describe the skills, knowledge, and character traits that influence a worker's potential earnings. If employers value the same attributes for several generations, parents with above-average human capital are likely to have children with above-average human capital. Families vary dramatically in the number of hours that their adult members spend doing paid labor. The relationship between a mature man's family income in adulthood and his family background fell during the 1960s and then remained stable from the 1970s through the 1990s.
