Race and gender in Icar
Icar is set 90,000 years into the future. The races that left Earth to live on the the Ariane 1001 space station intermingled for thousands of years, producing a single human race. That race then evolved over the 90,000 years to cope with the broad variety of worlds. The human race could have branched again but regular space faring kept the human race as one. Skin colour, gender, fitness and body shape morph in each individual human depending on their environment and choices. This is quite jarring for us living in the 21st Century but for the purposes of playing Icar, it gives you cues about the life of the non-player-character you meet.
While there is one human race, there are two machine races: the Droids and Automatons. Droids are the killer robots, whose simplified intelligence seeks to destroy all life. Automatons have philosophically driven artificial intelligence, which is immune to the Droids. We'll concentrate on humans here.
Galactic vs Local Cultures
Humans are still programmed with prejudices while growing up within their culture. There are two cultures at work here: the Galactic culture, which is influence via Gaia media (news, games and interactive stories) and the local culture via people they live with. Local culture tends to drive short lived fashions whereas Galactic culture drives long term traditions. Every local system can have its culture measured in how far from the Galactic norm it is. The more remote a system, the less travel there is and the further from Galactic norms the system will be.
For each topic below, Galactic and local cultural differences are outlined.
Skin Colour
In Icar, you skin colour changes depending on how much time you have spent exposed to sunlight. Spacefarers will have pale skin, while as those living on the surface of worlds will have darker skins. Unlike in the 21st Century, each individual human's skin colour changes over time. If you were born on a space station, your skin will be an pearlescent ivory; if you then lived a life on a planet surface spending long hours under the sun, your skin would turn a deep chocolate black over the years. From planet surface to space is the same process in reverse. Every shade in between. In this way you can tell where someone spends their time but not where they came from (unless they are very young).
Local cultures usually form a preference to the opposite of the norm for that culture. If you live on a planet surface then whiter skin is seen as daring, interesting and exotic. If you live in a space station then dark skin is associated with wealth, freedom and being exotic too. Bleaching and ultraviolet baths to try and emulate the other tone and go in and out of fashion. There are medical procedures that can fix your skin colour but they are expensive and in most local cultures are seen as something of a tacky joke.
Body shape
Most humans live on planets that have a gravity between 0.8G and 1.2G. Living on a planet with a higher G will make your muscle density thicker, while living on a lower G planet will give lower muscle density. There is no-muscle wastage, even for those that spend huge amounts of time in zero gravity; the human body has adapted to keep musculature at a minimum. Culturally, there is no preference for either; fashion throughout the Galaxy swings back and forth between being plump and thin.
Gender
In Icar, gender is a non-binary choice. Medicine has advanced to a point where gender can be invented such that it no longer matter what your gender at birth is. Although inventing genders isn't common, it is easy and allows a huge variety of options. For example, a couple can switch genders to facilitate having children naturally, which is particularly important as the Genus 2 mutation can kill the mother of a child. It is regarded in the Galactic culture as fair to take it in turns to have children.
As gender no longer matters, neither does sexual preference. People fall in love with other people, regardless of their biological configuration. Consummation can require a simple medical procedure first but this is viewed as a practical necessity rather than unnatural. As such, gender is no more a conversation point that changing the colour of your hair or choosing a new job.
Medicine can synthesize any organ, sperm, ovaries, eggs, wombs and any other component of human creation (except genetic code), taking humans completely out of the process if needed. The Galactic culture has chosen not to take that route except in extreme situations (such as in violent planetary environments).
Genetic Hacking
Our genetic code has long since been unraveled and understood by science. However, every social experiment with genetics has failed; often spectacularly and as such editing the human genome has been outlawed. That's not to say it doesn't happen but it is extremely rare (good fodder for a campaign plot). Genetic code comes inbuilt with chaos, which keeps humanity healthy and improving over time. Any kind of intervention causes the genome as a whole to become unbalanced and although one generation might be alright, the problems occur much further down the line as the chaos reasserts itself.
Bionics
While applying biological medicine to yourself to change gender/hair/skin is seen as natural, applying bionics is seen as unnatural, even across the wider Galactic culture. This is where the major philosophical divide appears between Humanists, who believe in obeying your genetic code and Technologists that believe that the future of humanity is in upgrades with technology. From the smallest Gaia neural interface to replacing everything but the brain, people with bionics (Borgs and Cybers) are generally seen as another race entirely, not to be trusted or treated equally. The Galactic culture is one of caution but locally the culture can swing wildly one way or another: from being a machine cult to a hippy paradise.
For most, bionics is a choice but there are many whose genetic code contains defects that cannot be corrected with biological medicine. If you wish to run a campaign that shines a light on prejudice and bigotry then use augmented humans.