Unless you see a reason to assume that your LO has it, I would assume that he/she doesn't. If you keep LO strictly gluten-free, you won't ever know if he/she has it - you can't find out without ingesting gluten. If LO has gluten occasionally - at other people's houses, at preschool, with Dad, etc. - and has a negative reaction (more than one time), then you would want to go down the route of figuring out if you want to pursue testing.
My daughter hasn't been tested, and isn't strictly gluten free - we are 99% gluten free at home (she's had cheerios, and shares wheat-based bread with daddy when I'm not home sometimes), and she gets gluten if we share a snack with friends or when she's at preschool (though she usually opts not to eat the snack). We've seen no symptoms, so I assume that she's not celiac at this point. I don't know if she carries the genes; she hasn't been tested. But we are aware of what to keep an eye out for, and will pursue testing if we feel it does become an issue.