At first I had a difficult time with this same issue. I wanted to yell at them and tell them to mind their own business but I never did. Instead I went back to something I did with my nephews before I had kids. If I caught my nephews staring at someone I would make them go up to the person (with me) and introduce themselves. Then I would ask the parent if the boys could ask a question about what the child was going thru. Most parents were more than happy to answer, others were annoyed, but it was my way of teaching them not to stare just because they don't understand. With this I started to introduce myself & my son to the people staring and/or snickering at him. I would nicely ask if they would like to know why he is so special, or if they have a question they would like to ask me about him. I'm not going to say it works everytime because it doesn't, but I feel I'm showing my son I'm not embarressed by him and more people need to learn to understand how different we all really are in the big world. I have explained to him he can only approach strangers like this with me only, not even with his dad. This is my way of keeping him aware of stranger danger at the same time. Most everyone who sees us on a daily or weekly basis now will stop and say hi to us and my son will wave and say hi back.