I believe -- in fact, I'd go so far to say that I know from experience -- that "perfect pitch" can be acquired -- and lost; it's *not* something you're either born with or not, as I had once been lead to believe. Like a lot of other things, it comes from practice.

I never thought I had any special talents for hearing pitch, and as a beginning guitar player (and again years later as a "re-beginner") I had trouble tuning, even with the help of a reference (pitchpipe, tuning form, etc.)

However, during an intense couple of years when I was playing virtually all day every day, I could tune damn near perfectly, for months after losing my little pitchpipe. I assumed for a while that I was only staying in relative tune with myself, but was surprised to learn, when playing along with a piano after weeks of solo busking, that my guitar was absolutely in tune, and did not require adjusting at all.

When I ceased playing with such obsessive regularity, I lost that unexpected tuning ability.