In the sense of living separately and indifferently, you could say I am estranged from my father. I haven't seen him since I was 4 (so it's coming up 20 years), he has never sent birthday or christmas cards or presents, and as far as I know has never rung or been in touch with me.
I did have the 'opportunity' to see him when I was 12 and my nana had died (his mother), but I didn't want to do that. The only thing I know that he has done 'for me' was pay child support up until I turned 19, which he legally had to do.
I grew up from the age of four without my dad, and I am very well adjusted. There are things that bother me about not having a dad such as while I was at primary school (5-12 years old), most of my friends had two parents which was hard to relate to. Also the fact that my father won't be escorting me down the aisle at my wedding will be difficult, but I will use Matt's dad instead, as he is the closest I have had.

I have also never celebrated a fathers day before.

There are things I have missed, but on the whole since I have only known this, I also don't feel like I have missed out on much. My mum raised me and my brother by herself and did a bloody good job of it. I don't know if I would have coped being on my own all those years with very young schoolchildren keeping me company...

I don't know how relevant that is to your query, but I thought I would share anyway... hope I have helped in some way!