All couples participating in this study must have a history of previous pregnancy together and no history suggesting subfertility. Participants in this study will be randomly assigned to one of two groups. One group will receive instruction about identifying the days when a woman is mostly likely to get pregnant from intercourse, using the Creighton Model FertilityCare System, and the other group will receive instructions about the menstrual cycle, fertility, and preparing for pregnancy. Randomization is stratified by age.