Hi Seansmom, I read your post and was prompted by many questions. Have you gone to any SPD sites to see if he fits the description? Hypo-sensitive? Is this the only issue your son has encountered? All other milestones: maturity, cognitive, behavior on track? If yes is your answer, then it sounds strictly physical. If there are any other issues then I would suggest you check out some SPD check-lists, and at the same time talk to your doctor. If your doctor is not helping, find another doctor. Toilet training issues can be apart of sensory disorders, but it sounds like your just starting to have bigger questions....I do have a blog that I have shared my journey with my sensory kids. It may help. I have twin boys who are seven. ONe is Hyper-sensitive, the other Hypo-sensitive. I have two separate posts describing the characteristics that can define a sensory issued kid, and the differences betweeen the different kinds. Look for my post: Hypo-sensory...I talk about my Everett. He is my one that was delayed with toilet training issues, connected with his SPD. Blog: qannie47.blogspot.com Good Luck! Qannie47