At first glance, My Friend Cayla seems harmless. The 18" tall talking doll, who comes with a hairbrush and mirror, answers questions, tells stories, and generally responds to almost anything she's asked. She also comes with an app so you can connect to her via your phone. She's been a kids' favorite since her debut in 2014.

However, Germany is no longer quite so fond of the adorable plaything. On Friday, the Federal Network Agency, which oversees telecom-related topics, banned the doll, citing its "unauthorized wireless transmitting equipment."

"Items that conceal cameras or microphones and that are capable of transmitting a signal, and therefore can transmit data without detection, compromise people's privacy," said Jochen Homann, the agency's president. "This applies in particular to children's toys. The Cayla doll has been banned in Germany."

The agency argues that the doll's Bluetooth connection could easily be hacked.

"There is a particular danger in toys being used as surveillance devices: Anything the child says or other people's conversations can be recorded and transmitted without the parents' knowledge. A company could also use the toy to advertise directly to the child or the parents. Moreover, if the manufacturer has not adequately protected the wireless connection (such as Bluetooth), the toy can be used by anyone in the vicinity to listen in on conversations undetected."

Cayla has also gotten into trouble in the U.S. Back in December, the Federal Trade Commission heard a complaint that the doll violates privacy rules. The dolls ask children for personal information, and the Electronic Privacy Information Center and the Campaign for a Commercial Free Childhood claimed that the dolls record conversations and send them to a company server without getting the consent of parents. Cayla is also being invesigated in the European Union, France, the Netherlands, Belgium, Ireland and Norway.