The FDA has just given approval to the DuoFertility Ovulation Monitor, a product made by Cambridge Temperature Concepts Ltd. as a wireless way to track ovulation patterns based on your body temperature, and accurately monitor fertility using other data users can input to the device's software.
This particular device is actually a wearable sensor and reader unit that is capable of measuring ovulation patterns, making sure you use technology in your favor to maximize the chances of you conceiving, although I am quite sure that other folks would use it otherwise, to ensure natural birth control methods are put into place. The sensor is worn under the armpit (I wonder how uncomfortable that might end up as), where it is capable of measuring subtle changes in basal body temperature, which is normally a pointer of when ovulation occurs.
The manufacturer offers a video to demonstrate how the device works.
Image via http://www.duofertility.com