Wanting to be part of the process, many humans imagine themselves to be an alien/human hybrid. They examine themselves in the mirror and take note of physical characteristics that seem unusual. They take note of any unusual talents they may have and judge this to be proof. As contactees seem to have special status without proof, why not they? Here again we are faced with disproving the proposition, but this proposition can be disproved. Hybrids would inevitably carry genetics from both species, and though these genetics might conceivably fail to express themselves on the claimant's external appearance, they would be instantly discernible to a geneticist under the microscope. The human genome is rapidly being mapped, and is public record. To disprove this proposition, challenge a claimant to have their chromosomes tested for abnormalities. To be sure, chromosomes from an alien species would be considered abnormal.
As none of our hybrids are currently living in 3rd Density on Earth, and as Special Children are just now appearing on Earth, claims by an adult or teen of hybrid status should be noted as false. Special children likewise would not be trotted out for display as they are placed carefully with discretion and protection from harassment a prime concern. Therefore, parent or relatives who claim an infant or small child to be a hybrid are false. These people are all simply publicity seekers.