How can you differ between a male and a female baby bird from its physical appearance?

My parents are bird owners and I've helped raise babies for a few years and honestly The only way to know a male from a female is if u get a DNA test. Sometimes males will be more colorful, and bigger but that doesn't mean its always going to be a male bird.

To DNA test a bird all u do is trim their toe nail a lil bit shorter and get it to bleed a tiny bit and u put a drop of blood on the DNA test card and mail it in.