Washington - Your best friend may not know when you last had sex, but it's possible that Facebook does.
At least two menstruation-tracking apps, Maya and MIA Fem, were sharing intimate details of users' sexual health with Facebook and other entities, according to a new report from Britain-based privacy watchdog Privacy International.
In some cases, those details, which are self-recorded by users in the app, included when the user last had sex, the type of contraception used, their moods and whether they were ovulating.
The findings raise questions about the security of the most private information in an age when employers, insurers and advertisers can use data to discriminate or target certain categories of people.
The information was shared with the social media giant via the Facebook Software Development Kit, a product that allows developers to create apps for specific operating systems, track analytics and monetize their apps through Facebook's advertising network.