Would this idea be too sensitive / too much information / generally a bad idea?
For example, I have a friend who is doing her computational biology PhD at a strong U.S. program, and her main research is about the illness of one of her family members, whom she unfortunately lost recently.
I have also heard of specialist (medical) doctors who got into their field because they suffered from the very illness that they are now trained to diagnose and treat.
For me, at a much lower level, at the MS Thesis level, I have a chance to work with a very well-known applied mathematician, who has joint appointments at our math dept and medical school. But, I don't have a clue what project I would like to initiate with him, other than about something that I have dealt with personally and medically -- and this topic could likely be within his research domain. Of course, I would be naturally very passionate about working in this area. I am always fascinated, when I see my own team of doctors twice a year to have discussions about my health.
If I could do a mathematical project about my own health issue, do you think that this is ... TMI? A classic "beginner's mistake" perhaps? Or, is it pretty common for applied mathematicians to dedicate some (or all) of their research to issues that they are intimately familiar with?