The Cortii are a distinct humanoid sub-species, legally recognised by interstellar governments as having met all the markers for recognition as a separate race.
Physically, we know the Cortii are based on artificially-generated bodies. Cortiian scientists have clearly managed to overcome some of the key challenges with the full cloning process, and Cortiians in active service show none of the health defects or challenges to independent thought that clones usually face.
The majority of Cortiians fall in the upper third of the height range for humanoid variants, a compromise that gives them a slight disadvantage in heavy gravity environments and smaller, closed environments, but which demonstrably gives them an advantage of reach and speed.
In colouring, they tend towards a mid-tone shade. Prolonged time in a closed environment leaves the majority pale or sallow, but even moderate exposure to ultra-violet light darkens skin tone quickly. Very few Cortiians observably experience burning in strong light environments short of severe over-exposure. Hair colour tends towards absolute shades, potentially as a result of the cloning process, and black, blond, and red are more common than in most humanoid species. Brown and other intermediate shades are rarer although not unknown. Induced shades such as greens and blues have not been observed to occur naturally. Eye colour shows a usual range.
Cortiians show an average range of genders and appear as a species to have very little by way of fixed sexual orientation.
Dissection has revealed that Cortiian bone structure is slightly denser and noticeably more resilient than the humanoid average. It can be conjectured that this results in cracked bone where most humanoids would suffer a fracture. Muscle tissue has been likewise modified, adding a little mass, but offering greater strength and resilience. Certainly, Cortiians heal observably faster than average; slightly faster under adverse circumstances, and significantly faster when able to rest and provided with sufficient nutrients.
Cortiians have slightly enlarged sinuses, resulting in a tendency to high, angled cheekbones. Analysis of nasal nerves indicates a high probability that Cortiians possess very acute olfactory senses. Eye sockets tend to be deeper, providing better-than-average protection to the eye itself, and eye structure shows that Cortiians have at least limited vision into infra-red and ultra-violet, as well as enhanced distance vision.
They also demonstrate resistance to a wide range of adverse environments, and metabolise a number of common compounds faster than average, especially those used in sedatives and other related medications.
Studies up to this time have failed to isolate the precise modifications that result in these variations, or in successfully reproducing the effects.