The lab technician inside Gattaca (who did the tests on Vincent) knew that Vincent was an invalid. How / when do you think he realized this, and why didn't he tell anyone?

Dr. Lamar asks Vincent if he'd ever told Vincent the story of his son. This is something that Lamar has asked Vincent many times, without ever telling Vincent the story. It is only at the final test that the doctor tells Vincent that his son admires him (Vincent) and wants to be an astronaut despite a genetic defect that will bar him from doing so. Vincent is sort of a role model for the genetically deficient.