Abstract: The present invention involves a device for family planning and/or countraception, whereby the device has a means for determining basal temperature, a means for input of the first day of the cycle, a means for input of the property of the saliva, a device for processing the data made available by the means, a memory device for storing at least some of the data made available and a display device, whereby the device for processing the data is designed such that a conclusion regarding the woman's fertility on any given day is determined as a function of at least some of the data made available by each means and this conclusion can be displayed via the display device.