A number of different causal mechanisms have been proposed to explain the onset of fertility declines in populations with previously uncontrolled fertility, but they have never been adequately tested. The present study identifies and tests five antecedents to family limitation practices in a sample of 755 currently married couples resident in rural Northern Thailand. The loglinear multiple regression models estimated indicate that couples in more developed districts, more modern couples, couples in which wives have more equal roles, couples believing that intergenerational wealth transfers favor children rather than their parents, and more wealthy couples, were all significantly more likely to be early adopters of contraception. Local development levels appeared to have the greatest net effects on the timing of adoption of fertility control. In addition, couples in areas where contraceptive services were more readily available were also significantly more likely to be contraceptive innovators, net of these five variables.