Actually, JK Rowling thinks so.
I haven't seen anything in the books to support it, and according to this article, he loved a guy, guy died, Dumbledore never loved again. So sad.
But it doesn't matter.
Not to me.
I'm rereading the 6th before finally reading the last one, and I got to thinking about the 'news'.
This does not affect how I read the books, I won't look for clues or hints, because it doesn't matter.
The only romances that matter in the book are the students', since the action primarily focuses on their lives.
Besides, teachers are asexual. And live at school.
Once you figure out what sex is, you realize that everyone with kids (even your parents!! ew!!!!) did it.
But not teachers, come on, that's just weird.
So that's why it doesn't matter to me - Dumbledore's love life isn't important to the story - it may have been in her head, but she didn't put it in the books.
Also, I'm sure the people who had conniptions over the devil-worship just love this, since all homosexual men are pedophiles and Dumbledore worked with children, OMG.
If it becomes a big controversy, more books will sell. Perhaps it's a ploy by Rowling to keep sales up, not that she needs it.
So far, everyone I've run into has said, "Oh, I love Harry Potter."
One of my relatives teaches at Stanford and (in June 2003) had at least 3 hardback sets - including the new 5th one.
The books are appealing to people from all walks of life.
Before the first movie came out, I was all, "I don't care, it's popular, I hate it." Then I read the 4 that were out, and loved each one.