Patent ID: 7438691

Claim:
A device for determining a fertile phase of a female human comprising: (a) a sensor for sensing concentrations of at least two ions in the eccrine sweat of the female, said at least two ions comprising at least a first ion and a second ion different from the first ion, said sensor comprising a first electrode for sensing the concentration of the first ion and a second electrode for sensing the concentration of the second ion, and generating output signals indicative of concentrations of the at least two ions in the eccrine sweat; (b) a processor for controlling the sensor to sense the concentrations of at least two ions in the eccrine sweat substantially simultaneously and at least on a daily basis; and wherein the processor monitors the output signals from the sensor to identify a distinct change in the concentration of one of the at least two ions following an inversion during a single menstrual cycle of the female which indicative of the female human being in the fertile phase.