" Perfect Pitch " is created by a mutated gene that is passed down through heredity. It ussually skips a generation, so if your mom had it then it would be passed on to your siblings.The generations the gene does not show up as perfect pitch the gene ussually shows up as some form of mild retardation.
You CAN NOT develop perfect pitch! It is a freak of nature. If you ever talked to anyone who has it (very few people do)they hear music in ways that we can never imagine, most people describe it to me as hearing colors. Imagine pushing down 11 keys on the piano and being able to identify wich note is not being played: that is perfect pitch. So if anyone ever tells you they have it put them to the test.
What the rest of us mere mortals have is something known as relative pitch.Each of us is born with different capabilities of relative pitch depending on how advanced are part of the brian that processes music is. Relative pitch can be improved upon through ear training excercises, singing, and dictation (transcribing).So those ads are a little misleading, you can improve your pitch, but you will never be able to develop perfict pitch.