I firmly believe that all of us have OCD to a certain level or extent.
ompulsive disorder (OCD) is a mental disorder where people feel the need to check things repeatedly, perform certain routines repeatedly
Yes, this is correct. I have OCD and while it does not "rule" my every day life.; it can cause issues at times.
Interestingly,cause of obsessive-compulsive disorder is concerned with identifying the biological risk factors involved in the expression of obsessive-compulsive disorder 
That explanation was a bit over my head. Can you express the same info in "laymans" terms, please?
ctivities include hand washing, counting of things, and checking to see if a door is locked.
Yes, I can relate. I have certain things I do in sets of three, my favorite number.
Some adults realize that the behaviors do not make sense.