or as many simply call it "NFP", is a holistic and healthy way of planning a family. Essentially, it is the ability to monitor fertility and to modify behaviors according to the intention of either achieving or avoiding pregnancy.

The Marquette Model (MM) system of NFP brings 21st century technology to NFP by using the ClearBlue Easy Fertility Monitor, a device used at home which measures hormone levels in urine to estimate the beginning and end of the time of fertility in a women's menstrual cycle. The information from the monitor can be used in conjunction with observations of cervical mucus, basal body temperature, or other biological indicators of fertility. The MM was developed by professional nurses and physicians at Marquette University in the late 1990s. A recent (2007) study published in the Journal of Obstetric, Gynecologic, and Neonatal Nursing demonstrated a 97-98% efficacy of the MM in avoiding pregnancy when taught by a qualified teacher and correctly applied.