But you just said that it had to do with DNA, having or lacking a Y chromosome. Tests have shown that far more than "1 in 1000" people have DNA that does not match their genitalia inside their body, even as many as 1/100, which puts the number above that of transgendered people. Most people do not even know they have it, like the person discussed in the link I provided. I very likely have Y sex chromosomes in my body, and they will almost certainly be there still (given the results of research into this) when I die, even if that is 60 years from now. If you are a man, you have a pretty good chance of having female DNA in your body, somewhere.
Genetic Chimeras: Are You Your Own Twin? - Scientific American Blog Network
And it mentions something that many don't think of, people with two different eye colors or two toned skin are more often than not found to be chimeras.
You have no right to see anyone's DNA tests, of any part of their body. That is HIPAA protected information. Why should they have to violate their privacy because of your insecurity and/or distrust? Plus, in order to determine if someone may be a chimera, in many cases, DNA would have to be taken from a number of different places throughout the body. A person could have that other DNA only in one body part, a part that is not tested on normal DNA tests.