To me, it's because of an emotional contrast- there's a conflict that isn't resolved, at least under the surface. Wierd. I like to look at it.
In my thoughts, this is a very good shot. As Rick said, it gets people thinking. With my shots, I like when I can steal time from people and get them to study the shot, to figure out if they like it or not. The longer the better. Clench them in the gut somewhere/how. This does with the twins what I would like to do with scenery and static oddities.
Here's a page from a link that IronFlatline posted awhile back. The links on this page freak me out.
http://www.simenjohan.com/x/2000_2001/index.htm
(BTW, I think the pyschotic-looking kid is my evil little nephew).
I find the work, although mildly disturbing, inspirational. This shot too.