One of the most important uses of Facebook Inc. ( FB ) and Alphabet Inc. subsidiary Google’s ( GOOG ) artificial intelligence is face recognition technology. Both tech behemoths have combined it with their data processing capabilities to develop new features in their products. For example, Google Photos uses face recognition technology to streamline searches and quickly identify people and objects in their photo stream. Facebook uses it to tag suggestions for photos that include users.

But their use of the technology could is under threat due to lawsuits. Facebook is already fighting a class-action suit from users who claim that the Menlo Park-based company is using their photographs without permission. The suit, which was filed under the Illinois Biometric Information Privacy Act, wound its way to California earlier this year. A judge in San Francisco ruled against Facebook’s bid to quash the suit. (See also: Facebook Loses Motion To Dismiss Privacy Suit ) . Google is facing a similar lawsuit from a Chicago resident, who claims that the company’s mobile operating system Android mapped a template of her face.

According to Alessandro Acquisti, professor at Carnegie Mellon University, facial recognition technology could also result in identity theft. In research conducted in 2011, he said that tagged photos make it possible for others to “link our face to our names in situations where we would normally expect anonymity.”

For both companies, the growing rhetoric against facial recognition technology could have serious business consequences. For example, it could result in loss of revenues. This is because facial recognition technology is a useful tool in creating a more valuable and comprehensive picture of users. For example, Facebook can identify user activities and interests through picture tags. In turn, the company will be able to sell this data, which it claims is anonymized, to advertisers.

Per research, revenues from facial recognition technology could be as much as $882.5 million in 2024. It could also hamper future product development for both companies and put them behind. Face recognition is part of biometrics , a field that is gaining traction in tech products that are marching towards singularity, an indistinguishable merging of man with machine. Apple Inc. ( AAPL ) has already integrated biometrics in its iPhone for sign on purposes. (See also: Biometrics Banking: Huge Prospects For Tech Profits ).

Earlier this year, both companies put their weight behind amendments to Illinois’ privacy law that sought to change the terms “photographs” and “scans” to exclude activities related to “tagging.” For their part, users have charged Facebook and Google with using photos without explicit authorization. This charge could also represent a potential solution to the problem. Both companies could present a notification asking users for their consent before including their photos in the database.