What do you assume to be true about ______?

I was asked to think about a vulnerable population that I don't know very much about, or that I have a slight fear of.  When I was first asked to think about a group,  my mind drew a blank.  I'm not saying I know everything about all the populations in the world, but there wasn't a particular group that came to my mind that really scared me.  Throughout the week, I thought a lot about this subject, thought about if a certain person walked into the store I managed, which kind of persn would I most be hestitant about.  I still don't have a very clear idea, but a group that has come to mind, (and I do apologize if I offend anyone, I want to be more educated about this topic) is people with Down Sydrome. 

I would like to consider myself an intellegent person, and I undersatnd my fear of people with Down Sydrome is irrational and unneccesary, but it's one of those things I can't help.  I think my fear stems off of not knowing what they are capable of.  I know each person with Down Sydrome has different severities of the sydrome, so not knowing how large their brain capacity is, or not knowing what kind of things make them angry, because I have heard they are an unstable population, whether you are their best friend or not, they may snap.  But I suppose any person could.  I have also heard that people with Down Sydrome are very smart, but possibly only smart when it comes to certain topics, like some may know everything there is to know about air planes, while others may know everything about boats.  That part slightly scares me, because it makes me wonder how they decide that's the most interesting thing, and that's what they decide to focus on so much instead of other things. 

I think the biggest struggle I will have on doing research about this is going out of my comfort zone and learning about a population that has frightened me for many years.  I know it will be refreshing once I learn more about them.  Another struggle is the guilt.  Voicing that I am afraid of a particular group makes me feel guilty, mankind has come a long way in making people equal and making everyone understand each other, and I take pride in myself for trying to give everyone an equal oppurtunity in my mind when I first meet them, to try and not past too much judgement, but deep down, I haven't given everyone that equal oppurtunity and I feel guilty for doing so.  I hope by doing this research, I can educate myself better.