* Why does Gattaca (the facility) keep testing its employees' genetic material once they've been certified as genetically pure? This wouldn't be a problem if they did it to catch Vincent, but they've never had this problem before.
** They're actually drug tests, but the movie's AppliedPhlebotinum is [[YouFailBiologyForever ubiquitous instant genetic screening]] - the computers analyze genetics at the same time just as a matter of fact.
** There's also the drop of blood employees have to give via finger prick upon entering the building, which replaces photo [=IDs=].
*** Exactly: In the world GATTACA sets up, genetic material is used as the primary form of identification. That's why Vincent is INVALID (that is, he's not in the database of Gattaca babies, so his identification is "not valid") but Eugene is VALID despite [[FridgeBrilliance being an ''invalid.'']] (Invalid- n. 1. an infirm or sickly person. 2. a person who is too sick or weak to care for himself or herself.) The daily drops of blood are equivalent to the access cards used by some secure buildings, while the more intrusive blood and saliva testing seems roughly equivalent to looking at a driver's license.
** Jerome must have been quite famous in his time. So how come nobody seems to know that he ended up in a wheelchair after his suicide attempt, and it's absolutely okay and not questionable to see him (or Vincent, actually) walk?
*** Think of the last Olympic swimming race you watched. Do you remember who the second place guy was?
*** No, but I bet his competitors and others in the swimming community did. On the other hand, it does seem likely that he could quietly announce he was tired of swimming and would be pursuing something else, and be done with the matter without much question.
*** And how many professional swimmers are really working at Gattaca?
*** Social stigma perhaps. He gets second and so people forget him. When he tries to kill himself, he gets admitted to an invalid hospital or gets treated like one because no one believes a valid would attempt suicide and fail. So as far as the valid community goes, he just kinda left. This kind of situation is echoed in Vincent's interaction with the head janitor. Merely by wearing the suit and being shown the door as a valid, Vincent gets completely different treatment from someone he's already met before (and even worked for!) who also shows no signs of even recognizing or remembering him. This situation is not as far-fetched as you might think - there is a famous story of a journalist talking with Marilyn Monroe while they're walking down a busy New York street. He asks her why no one seems to be recognizing her despite wearing little in way of disguise. She replies along the lines of "Oh, you want to see ''her''." and affects her Marilyn Monroe persona. ''Instantly'' people begin flocking to her and recognizing her.
*** Jerome's competitors would likely just be happy that a great swimmer is no longer standing in the way of their own success. If his attitude at the beginning is any indication, he wasn't likely a nice guy before that so friends are fewer. It could also be more of an implication as to how much of a CrapsackWorld the film is set in - failure means that you get abandoned.
* The 'Geneticists' would eventually put themselves out of business because the 'Valid' children would produce 'optimum' children thus removing the need for them.
** But the valids could have even ''better'' kids with more genetic playing.
** Even if you could perfectly screen everyone's DNA sequence at birth, new mutations in one's germ line could still pop up spontaneously. Unless science has gotten to the point where they can completely eliminate all new mutations, there's still potential work for geneticists to do.
** Not to mention recessive alleles. Unless science has gotten to the point where they can get around THEM, too.
** The advertising would be pushing "Better safe than sorry!"
** Short answer: Unless you can stop all factors that influence genetic drift, you're not going to stop mutations. Only some of those factors involve your parents. In addition, you're also making the assumption that there are some sort of EvolutionLevels involved which there aren't and/or that perfect/optimum is some objective standing. In context of the film, it isn't - they're called designer babies for a reason and not perfect babies. They're being designed for what their parents want based on social pressure. This can mean if people want babies with purple hair, that becomes a thing. And in the movie itself, there is mention of a 12-fingered pianist - additional digits are genetic anomalies but either the parents of said pianist wanted him/her that way OR like Vincent, he passed it off as a 'superior' genetic trait and people flocked to him because of it. Lastly, look at Vincent himself - it's not that he ''had'' a heart condition but rather he had a high ''chance'' of a heart condition - a chance that he would develop one before the age of 30. This applies in reverse too (See Doctor Lamar's son) - it's impossible to strictly control what's happening since they're not building a machine (like their marketing line says), they're just stacking the odds. So the companies would always have business because people are fickle.
** Additionally, the scene in which Vincent's parents "order" his younger brother shows the geneticist offering choices such as hair color and eye color. The geneticists clearly expect purely cosmetic factors to be part of the package, which means there's always something to market.
** What we see here is really just scratching the surface of what genetic engineering could do. Once they had the process down specialized body types (eg, body builder vs. swimmer), increased endurance, etc. would be viable options. Once it becomes accepted there's no real reason to stick so closely to the norm.
** The geneticist tells Vincent's parents "This child is still you, simply the best of you." It's possible they don't eliminate the genetic issues rather than suppress them.
* The murderer the detectives are seeking turns out to have been someone genetically engineered to be calm and even-tempered; which means that the murderer must have been [[TranquilFury very calm and rational]] even while ''brutally smashing the guy's skull''. The murderer was also very likely aware that making the crime look like it had been done in a fit of rage would shift suspicion onto any "invalid" in the company. That's a pretty solid case for convicting the culprit of "cold and premeditated" murder in the first degree in court.