[LazyPup]

You wife may be correct. In some rare instances when the atmospheric pressure is high and a roof vent is in the vicinity of an open window sewer gasses can get back into the structure in the same manner as would smoke from a chimney. It is for that reason that the codes list minimum distances a roof vent opening may be from a window.

You may examine the problem from both viewpoints. First, make sure all the traps have and adequate supply of water, then examine the location of the roof vents and see if there are any windows or other openings in the vincinity where the gases could get back into the structure.