I've seen it too much to know that it (perfect pitch) exists. If it can't be learned and is just an anomaly, then there is no hope for any of us to ever try to learn how to do anything. Some teachers believe that teachers are born and one can never learn to teach. If that's the case, why are they teaching if they believe no one can be taught? Good news, you don't have to have perfect pitch to excel at your instrument or songwriting. FWIW, I don't see how perfect pitch doesn't ruin enjoyment of music, because everything has something wrong with it. It's like taking a tape measure or level to your house. All you would see is the imperfection.