Part of the point of the first Metal Gear Solid is that genetics isn't as important as training, experience, and strength of character when it comes to what makes a soldier, with Solid Snake, who is revealed in a post-credit scene to be the "inferior" clone of Big Boss despite Liquid's ravings* overcoming the implicitly and explicitly superhuman members of FOXHOUND, his genetically superior twin, and the genome soldiers who were modified to b genetically similar to Big Boss through raw skill and determination.
...But even in that same game Liquid was exposed to the FOXDIE Virus multiple times and it still took him hours to die(and according to supplemental material his heart stopped about a minute before he collapsed) when everyone else had a fatal heart attack within minutes of exposure and they do explicitly state that the Genome soldier project did increase the physical abilities, intelligence, and aptitude for weapons and vehicles of all test subjects. Liquid also shrugs off more damage than every other boss in the game combined.
Various prequels and side games, meanwhile, confirm the existence of biological superpowers in the setting and show Big Boss showing off superhuman feats of strength(overhead pressing away the leg of a metal gear trying to crush him,) toughness, and regeneration(recovering from the prolog of MGS3 in a week, anyone?)
The game presents the concept as being silly but... No, there was merit to the theories about Big Boss's apparently superhuman genetics and Les Infante Terrible and the Genome Soldier Project proved that there was a genetic component to his apparently superhuman level of skill and aptitude.
Kind of undermines the morale.
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And MGSV kind of undermines the moral of 2: "Real Experience and Individuality wins out over Simulated training and trying to make people into psychological copies of other people" being undermined all to hell and back by "this random guy gained all of Big Boss's skills and physical ability from fake memories and being gaslit into thinking he was Big Boss" Venom Snake getting all of Big Boss's powers from being made to think he as big boss proves the "memes" theory that the Patriots were testing in 2