A quantitative process for monitoring female fertility cycle wherein the process involves directing a laser beam, preferably generated by a diode laser, onto an area of a slide containing an air-dried sample of a female body fluid. The diffraction pattern resulting from the sample is detected by a two-dimensional photo diode array and analyzed by a microprocessor. If a ferning pattern exists, such pattern will generate a characteristic structure in the diffraction pattern which is then detected by the photo diode array. If no ferning occurs, the corresponding diffraction pattern will be structureless. The microprocessor is programmed with an algorithm to produce a quantitative index of ferning indicating quantitatively the ferning level. Preferably, a plurality of spots on the sample are measured to determine the ferning level at each spot, and the microprocessor then makes a final determination as to final ferning level on the basis of the test results of all of the spots. This significantly increases the reliability of the final test result, since a defect at one test spot or anomaly of one test result will not be fatal to the final result.