mercury is the most obvious culprit, but there is lead, cadmium, aluminum, arsenic and a bunch of other metals that can be harmful too. If you or your wife had mercury amalgams, that can be passed. There is arsenic in the water, lead in the soil, mercury in fish. It's not impossible to be poisoned just because you don't get immunized. So definitely look into it. I'd test it with DMSA and alpha lipoic acid. Your child is worth it.
Lots of luck
Tami Wilken