The 1981 Rural Demographic Survey focused on current and retrospective fertility mortality and migration information collecting data at 50000 households in 12 provinces of Ethiopia. Patterns of primary and secondary infertility by province and cohort showed a clear decline of women never having a child; having a 1st child but not a 2nd; having a 2nd child but not a 3rd. Childlessness dropped from 12% of the earliest cohort to 5%; 2nd birth declined from 16% to 6%. Childlessness varied from 20% to 3% in the earliest cohorts (women aged 59 or older) compared to 12% to 2% in the most recent cohorts (women aged 30-39). Almost all provinces showed a decline across cohorts. Infertility is commonly attributed to gonorrhea with high prevalence in Ethiopia and other sexually transmitted diseases (STD) although antibiotics (penicillin chloramphenicol and tetracycline) have reduced their incidence. A maximum of 2.2% increase of fertility was observed in a 5-year period by eradication of excess childlessness. In Ethiopia changes in primary fertility increased fertility by 1.5% between 1970 and 1980; and cohort trends in primary and secondary infertility increased total fertility by 4.5% during this period. In Arsi province the odds of childlessness increased by a factor of 2.3 if the woman was Christian and not Muslim. Christians also had a higher rate of childlessness in 2 of the 12 provinces. Ethnicity also played a role: in 5 provinces the Amara had a higher rate of childlessness than the Oromo indicated by an odds ratio of greater than 1.0. The Amara had 1.5 to 2.7 times the Oromo childlessness levels. Patterns of childlessness were attributable to STDs whose recent decline was caused by the availability of antibiotics. The implication of STDs only in infertility is not entirely plausible in view of the traditional structure of Ethiopian society. Therefore more research is needed on sexuality marriage and the family.