US-based supermarket chain Target was discovered to be quietly using a 'pregnancy prediction algorithm' to predict the pregancies of its customers, prompting a backlash about privacy abuse and poor transparency and ethics.

New York Times' Charles Duhigg reported that a father had discovered that his teenage daughter was pregnant when he complained to a Target store in Minneapolis that she had received pregnancy-related coupons.

Target calculated the girl was pregnant by combining data from individual purchases across approximately 25 product categories and sociodemographic characteristics from public records databases to to assign each shopper a 'pregnancy prediction' score that would enable the retailer to send coupons and other marketing information.

It also transpired that Target had been producing brochures that had some non-baby merchandise sprinkled around the baby goodies, so the newly pregnant women didn't realise they had been targeted. 

The controversy resulted in a debate about the need for clear, visible communication and the informed consent of customers, including whether privacy and terms of service are sufficient to notify consumers of the use of data mining techniques.