I don't know if I was born that way, because I had no attractions to anyone pre-puberty. It was when the hormones kicked in at puberty that I felt a sexual attraction toward those of the same gender and no sexual attraction toward those of the opposite gender. Also, I wouldn't consider my sexuality to be fluid so much as it is solid.
"Never trust a fox. Looks like a dog, behaves like a cat."
~ Erin Hunter
~ Erin Hunter