This study is an examination of social origins, educational level, and career mobility in relation to a series of events concerning fertility within marriage; namely, timing of marriage, timing of first three births within marriage, and family size. Data were analyzed for a sample of 1,029 engineering graduates from two large west coast universities. Respondents' educational level was positively related to the time interval between college graduation and marriage and the time interval between college graduation and birth of first child. In general, intergenerational mobility preceded marriage and initial reproductive behavior. An intercohort comparison of graduates revealed, however, that more recent terminal bachelor's degree recipients tended to marry and begin families prior to graduation. Social origins played a small part in fertility behavior-in the timing of the second child. The finding that career mobility was positively related to time interval between college graduation and birth of first child as well as inversely related to average birthdate of second child indicated some support for the fertility/mobility hypothesis for engineers during the early career years.