Hi, It angers me to be told by some they don't care or want to know the sex of their parrot. It is a form of crulety. It only costs $20.00 and gives you a great deal of understanding into behaviour. I have never recognized any of these terrible hormonal experiances I hear of. Probably because I know the sex of my parrots, parrots bite for basicly three reasons, fear, anger, jealousy. I have three small scars on the back of my right hand from the only time my girl ever truly bit me, that was because I was talking and ignoring her jealousy of the female amazon on my other shoulder. Many humans don't realize it even in their own specied but sex makes does a diference. D.D.