Abstract: Despite heightened awareness of fairness issues within the machine learning (ML) community, there remains a concerning silence regarding discrimination against a rapidly growing and historically vulnerable group: older adults. We present examples of age-based discrimination in generative AI and other pervasive ML applications, document the implicit and explicit marginalization of age as a protected category of interest in ML research, and identify some technical and legal factors that may contribute to the lack of discussion or action regarding this discrimination. Our aim is to deepen understanding of this frequently ignored yet pervasive form of discrimination and to urge ML researchers, legal scholars, and technology companies to proactively address and reduce it in the development, application, and governance of ML technologies. This call is particularly urgent in light of the expected widespread adoption of generative AI in many areas of public and private life.