A new smartphone app is being used by some women as an alternative to the birth control pill. Natural Cycles is supposedly 93 percent effective.
The app was developed by a pair of married physicists and is billed as the world's only app to be certified for the use of contraception. More than 200,000 women in 161 countries are already using the app.
Although the app has been approved by the European Union, it has not yet been approved by the FDA for use in the United States.
