Modern technology makes it possible to gather health data from a variety of sources and devices—like smartwatches that track exercise and sleep, period-tracking apps, and electronic health records. This data can be combined to, for example, drive research or train algorithms. But who gets to decide how it is used and under what conditions? Is it the individual, private companies, or the government? This research project explores, from a legal perspective, how individuals and institutions can cooperate to create democratic and inclusive models for collectively deciding how health data are used.