THank you both for your replies. I just don't know because it came on so suddenly. I had a wonderful childhood, had lots of energy, spent my highschool years in cadets and working, then I did a year of fulltime postsecondary. I know that a lot of people have said that they knew they were sick all of their life, but that isn't the case for me. I had the surgery, suffered from a pulmonary embolist and then I just didn't recover. It just seems that it came out of nowhere and the fact that they cut pieces of my sympathetic in order to fit screws into my spine has always made me wonder. It's just so hard to know because I am not a doctor and they have done this surgery so many times without POTS as an outcome. I fear that if it is genetic I will pass it on to any children that I have. I guess I just feel like I need to know but I don't know if I'll ever be able to know for sure.