Right after the birth of our first child and during my final year of fellowship, I was diagnosed with an extremely rare and aggressive cancer. I could write many things about this: the difficulty of going from full-time physician to full-time patient and the loss of professional identity that comes with that. Knowing enough about what's going on medically to be terrified, but not enough to be able to sort through the data on my own. Dealing with insurance companies from the other end. How my views about aggressive treatment, for what I know is an abysmal prognosis, suddenly changed when I pictured my child growing up without her mother. And the emotional discomfort I know I cause some of my clinicians, because they cannot help but see themselves in me. But these are hard realities of life, not things that can be “fixed” by my medical colleagues. Instead, I want to focus on an incredibly frustrating thing that the medical community can do something about: the “lack of data” regarding rare diseases, which now defines my life and care.