For all their genetic improvements, the Culture is by no means eugenically uniform. Human members in the Culture setting vary in size, colour and shape as in reality, and with possibly even further natural differences: in the novella The State of the Art, it is mentioned that a character "looks like a Yeti", and that there is variance among the Culture in minor details such as the number of toes or of joints on each finger. It is mentioned in Excession that:

Some Culture citizens opt to leave the constraints of a human or even humanoid body altogether, opting to take on the appearance of one of the myriad of other galactic sentients (perhaps in order to live with them) or even non-sentient objects as commented upon in Matter (though this process can be irreversible if the desired form is too removed from the structure of the human brain). Certain eccentrics have chosen to become drones or even Minds themselves, though this is considered rude and possibly even insulting by most humans and AIs alike.

While the Culture is generally pan-humanoid (and tends to call itself "human"), various other species and individuals of other species have become part of the Culture.

As all Culture citizens are of perfect genetic health, the very rare cases of a Culture citizen showing any physical deformity are almost certain to be a sort of fashion statement of somewhat dubious taste.