I was just reading an article that explained that repeated and long term exposure to false information will always leave a trace. Even years after a person learns that the information is wrong, and now knows and accepts the correct information, his reaction is slightly influenced or delayed because of the lingering false info.
So I guess we all have the same. It's an unconscious effect of how our brain works.
Congrats with your son-to-come, best wishes for him and his parents!