Parents can transmit income and wealth to their offspring directly through bequests and gifts of financial assets. Parents can augment a child's skills and traits through the provision of, for example, education, diet and doctors. Biological parents also supply the genetic endowments which provide skills useful in the labor market. Although practically a virgin territory, it is important to estimate the effects of genetic endowments and common (mostly family) environment on earnings and on other indices of individual attainment in order to gauge the effectiveness of programs designed to improve equality of opportunity. Also if genetics and common environment are not controlled for, biased estimates of regression coefficients of observable variables, such as years of education, often are obtained.