Was Snape the father of Harry?
No, Snape is definitely not Harry’s dad. James Potter is Harry’s dad. There is no chance that there is ambiguity or mystery here. Snape was a rival for the affections of Harry’s mom (Lily).
How is Snape related to Harry Potter?
As Rowling explained in a series of tweets, Snape loved Harry’s mother, Lily, and his unrequited affection drove him to resent Harry’s father, James — and by extension, Harry himself.