I know in New X-Men, Wolverine said that Laura was his sister but I can't help but thinking that she's more like his daughter. And I'm not alone. There are a lot of other fans on comicvine who think she's his daughter and there are those whose thinks she's his twin sister. 
  
So what do you guys think?... 
Daddy or very older brother? 
And, call me anal, but i would appreciate it if you guys gave me explanations and/or examples from comics! thank you!

well you know what i think already of course. lol.
by the way, id like to point out that i consider you more like my sister,
therefore you are now my sister...

I know how technically she's a clone, but based on the way he treats her then I generally think of him trying to have a fatherly relationship with her. 

i think this has been done before the answer was gentically shes his sister  but relationship wise its more like a dughter

"i think this has been done before"