sewer smells from my toilets

Are the toilets tight to the floor, or can you move them in a twisting motion? It's possible the toilets have loosened after the first year, causing the wax rings to break their seal, allowing vapors to escape. Sometimes you can tighten them down (carefully) again but i usually replace the wax ring, then tighten again in a few weeks and then check them again after a few months.