Metal Gear Solid
Les Enfants Terribles ("the terrible children") project (introduced in MGS1), was a plan launched in 1972 to artificially reproduce the ultimate soldier. The subject chosen for this project was none other than Big Boss, who was already proclaimed as the world's finest soldier. The said goal for this new project was to create a clone of Big Boss in terms of physique, prowess and potential. Natural and Analog cloning techniques, as well as the "Super Baby" method were used to produce two clones: Solid Snake and Liquid Snake.
However, this was done without Big Boss' knowledge. After finding out, Big Boss left The Patriots, therefore leaving the group with no icon, as Big Boss was the icon of the Patriots. It was revealed that Zero, who was in charge of The Patriots prior to Big Boss' departure, was afraid Big Boss would leave, thus Les Enfants Terribles was carried out. Ironically, this led to Big Boss' departure. The actual goal of Les Enfants Terribles was not exactly to create the ultimate soldier, but rather to spawn a new Big Boss icon for The Patriots.
Solid Snake, Liquid Snake and Solidus Snake are all products of Les Enfants Terribles project. Liquid Snake believed that Solid Snake had the superior genes of Big Boss after learning about the project. But in actual fact, it was Liquid who had the dominant genes, and Solid Snake who had the recessive and "inferior" genes.
Les Enfants Terribles project managed to create two imperfect clones of Big Boss, one containing dominant genes, and the other with recessive genes. However, the project also managed to create a "perfect clone" of Big Boss. A balance of both Solid and Liquid Snake. One who contained the exact genes of Big Boss and retained the same qualities and features of Big Boss: Solidus Snake. It is later revealed that the clones Solid and Liquid were actually born from a real, live surrogate mother, and not from machines. It was EVA; who was a part of the experimental project, and participated as the surrogate mother of twins imbued with Big Boss' chromosomes.