Who ever examines their own chromosomes? I’m a trained biologist and have never looked to be sure I really have a Y chromosome.
When I took genetics in community college, we cultured our own blood cells and treated them with colchicine to prevent them from undergoing mitosis, although the DNA was still replicating. We then made karyotypes of our own chromosomes, once they were nice and fat from replicating without dividing for several rounds. My karyotype matches my phenotype. :)
I read recently of a biology teacher who has stopped having his students do genetics experiments on themselves, because the chance of students learning something shocking was too high (about one student per class was unaware of something major, e.g., that his father is someone other than he believed, etc.). He switched to having them study the genetics of cats, since every student knows or owns cats and nothing they find out about their test subjects will be shocking.