Are fertility differentials by education converging in the United States?

"According to the theory of demographic transition, fertility differentials by education tend to become strongly negative in the early stages of transition, because family limitation tends to catch on first among the more educated. As the transition proceeds, contraceptive use diffuses to the less educated, and fertility differentials by education eventually tend to reconverge. The question addressed here is: Do fertility differentials by education disappear or become positive in advanced industrial societies? Evidence presented in this paper indicates that in the United States they do not. As late as 1990, the latest year that we consider, fertility differentials by education were still strongly negative." (SUMMARY IN ITA AND FRE)