Scholars of sex differentials in attainment in the labor market have long looked to the division of labor in the family--especially childbearing and rearing--as one source of these differentials. This study assesses the effects of the first birth on the career orientation and job characteristics of young adult males and females, using data from the National Longitudinal Study of the High School Class of 1972. It tests the hypothesis that those who become parents differ in their views of work even prior to the pregnancy that produces the first birth and that parenthood produces changes in career orientation over and above those existing earlier. The study also examines the average job characteristics of employed mothers and fathers to assess changes in these around the first birth. The results of the study show that mothers differ from nonmothers in several key respects prior to the pregnancy and that the first birth results in further changes. For men, no evidence of initial differences between those who become fathers and those who do not is found, and effects of parenthood are shown only for general career expectations. The results give some indication that new fathers become less focused on their careers in the years around the birth of their first child. (KC)