That doesn't really make sense. Cognitive dissonance may cause a smoker to rationalize their habit even though they have also been a non-smoker. In fact you could argue that cognitive dissonance is more likely to affect a parent than a smoker, as parents don't have the alternative option of quitting.
You could argue that non-parents may also be under the influence, but having formerly been a non-parent doesn't necessarily mean you're not rationalizing your choice to make you feel better about it.
You could argue that non-parents may also be under the influence, but having formerly been a non-parent doesn't necessarily mean you're not rationalizing your choice to make you feel better about it.