Timnit Gebru, a prominent artificial-intelligence computer scientist who helped pioneer research into facial recognition software’s bias against people of color, said she was abruptly fired from Google for sending an email criticizing the company’s treatment of minority employees and saying she felt “constantly dehumanized.”

An artificial-intelligence service freely available on the Web has been used to transform more than 100,000 women’s images into nude photos without the women’s knowledge or consent, triggering fears of a new wave of damaging “deepfakes” that could be used for harassment or blackmail.

Women who have used period- or pregnancy-tracking apps found ways to obscure their identity, using a system of aliases and throwaway email addresses or only recording scraps of information without giving away the full picture of their health.

It was her face. But it had been seamlessly grafted, without her knowledge or consent, onto someone else’s body: a young pornography actress, just beginning to disrobe for the start of a graphic sex scene. A crowd of unknown users had been passing it around online. She felt nauseated and mortified: What if her co-workers saw it? Her family, her friends? Would it change how they thought of her? Would they believe it was a fake?