In North America and Europe with your two year old Amazon, you should have been provided a Hatch Certificate that included its Parent's Species, Breeder information, Prior Owner information and commonly a DNA sex determination. Most include information regarding Prior Avian Medical Professional's contact information.
A very long way of saying that short of guessing you're Parrots sex. A DNA Test is required. If you have not had your Parrot into for a 'new parrot' examination its time to set an appointment for a health check and a DNA Sex test.