My childhood, and my parents, and their relationship, and my relationship with them, is very, very different from that of most of my friends, and very different to my husbands experience.
Basically, to be coined as simply 'dysfunctional' it would have had to greatly improve! It was straight-up ODD, at best.
There are plenty of people who come from loopy childhoods who go on to have happy, healthy, successful adult lives.
Many of my friends are people that I have known for years and years, so they know the deal. New people are not really told the deal. If I get to know them better, over time, I will let them know the deal, in bits, as I see fit, and when, and how, I feel comfortable. I'm not hiding anything. I'm not ashamed. I just let trust develop at a natural pace, and then I open up about things like that. Which is actually quite healthy.
As for dating, when it gets a bet serious, because it is a different kind of closeness, it is something that gets discussed sooner, and in more detail. Which is always a bit uncomfortable. There is always a slight fear that the 'sins' of my parents will somehow transfer onto me. It would not be the first time I was unfairly judged for their behaviour.
I have also had the experience of having someone I was involved with get sort of 'stuck' on that topic. It is very frustrating. I really don't want to talk about my dysfunctional childhood over dinner at a lovely cafe. Who would? It is not fun for me. That is not a fun date.
I think there are a few reasons people involved romantically with someone who came from a dysfunctional childhood get stuck on the topic. It could be that they are so interested in you that they want to know more about you, anything and everything, and that kind of childhood is very strange and new to them, so that is what they ask about. It could be that they slightly fear that the person they are dating is 'more messed up' than they are seeing because of what they went through. And they are trying to figure out if that is the case, or not. It could be that they are thinking about children and wondering if the parents behaviour is genetic, and could be passed on the their kids.
It could just be because it is all so strange and unreal of a situation to them that they are fascinated by it all, as if they are reading a really good book.
I have asked people exactly why they keep asking about it. Many times, they were unaware that they were doing it. I have found, (for me), that that is the best way to start. When he/she asks again, politely ask them why they keep asking about it. If they say they do not know, I offer up some of the examples that I have provided above, and ask if it is any of those reasons. I think it puts their behaviour in perspective for them.
I then explain to them that I am happy to answer their questions (if I am happy to do so), and I explain that it is not something I really enjoy talking about. People usually understand that.
Also, just so you know, you have the right to say, "I don't want to hurt your feelings, because I care about you very much, but I don't really want to talk about X with you right now. I'm simply not ready yet. It is not a comfortable topic for me. I will talk to you about that when I feel ready."
Most people, if they care about you, and like you for who you are, just want to understand it all a bit better. And they do not realise that it makes you feel uncomfortable!
You have the right to disclose what you want, when you want too, to whomever you want to disclose it too - and you have the right to NOT disclose anything you are not comfortable disclosing, to anyone, whenever you don't want too - even if they ask.
And you have the right to ask people WHY they want to know, and decide what you want to disclose, right then and there!
I hope that helps a bit.