The reality is that most atheist parents won't talk about deities (existence, non existence, possibility of existence) whatsoever, because deities aren't (for obvious reasons) part of their worldview at all. So I'd find it surprising if a conversation about the possibility of existence of gods would come up in most atheist households.
That was the case in our household when our kids were growing up, and is still the case now that our grandchildren are on the scene - religion just isn't, and has never been, a part of our family dynamic.
The only time religion has ever been an actual issue was (surprise surprise) in relation their education, although less so with the grandchildren where it seems schools (or their schools at least) are now more aware that some families simply don't want their children exposed to acts of religious worship as opposed to learning about the social, historical, cultural and political effects of religions in general (which is essential).
The only issue we had was when our oldest daughter came home from primary school with a permission slip to allow attendance at a church service locally during the school day - we sent it back saying we didn't give consent, and that same day got a note back asking one of us to arrange to see the headmistress at our earliest convenience - I remember the exchange very well.
She asked 'why', and I simply replied that we didn't do religion as a family and didn't want our daughter to be exposed to acts of religious worship until she was old enough to think critically for herself about religion: at the time she was 7 years old. I remember the next bit well - her sneering reply was along the lines of did we have the same objection when our daughter was christened, and when I explained that she wasn't christened and neither was I (none of our kids/grandkids are) she looked at me as if I had just admitted to killing Bambi's mother!
I then told her that she would just need to make other arrangements on that day which she did, and it turned out that other parents had refused permission, and thereafter we had no similar problems later as our son and younger daughter went through the same primary school, and by the time they were at secondary school religious services in local churches were discretionary since they were never held during the school day.