I just have to throw into this conversation that 90% of the characters I've seen at a table grew up SINless in the Barrens, but people here are put off by the idea of actually playing a young child SINless in the Barrens. I find this incredibly ironic. How many characters have you played that were never SINless in the Barrens, I wonder?
Some of us are under no such illusions. And having traveled to over 30 developing or 3rd world countries, I don't think you want to know the sad, soul breaking things I have seen....
But there are some very large problems with this concept - for most races- before you get to moral implications.
For the most part, trying to play a child in such an adult themed game, realistically, is going to have some serious issues. Take your average 12 year old, and compare that to your average 30 year old.... By all measures of physical capability, the average 30 year old is going to be almost twice as strong, much more endurance, and have much better fine motor controls.
The mental stats in SR don't reflect educational level, but they do reflect someone who is past their formative and investigative years, not to mention the dept and breadth of learning experience that simple living provides.
So if the average adult person's stats are 3, what is the average stats of a preteen? 1? 2? Now is that playable?
Then you're on to knowledge skills. A preteen is just learning complex tasks and to cope with complex instructions, while an adult, just by the fact of living, has had time to learn these skills, and techniques.
The average human has 28 skill points, with an average skill rating of 3 to 4. So what is appropriate for a preteen? 14 skill points with no skill above 3???
Not looking good for survivability.... But that should be expected. The person is, after all a preteen.
Now, things get REALLY murky when you throw in metahumans into that soup. It's Canon that an Ork reaches physical maturity at around 13 years of age, but not the mental maturity. Which leads to all sorts of problems socially. After all, Little Johnny punching Ben because Ben called him a "booger Brain" when Little Johnny is six foot eight, 200 kilos and has the strength of a body builder is a bit of a problem... ( And in Lore, this is covered by the mentions of racial hatred, social groups, hate groups, and other pieces of lore and fluff).
Even with an Orks maturation rate, it is still assumed that the Ork character has had the time to mature mentally and emotionally, and when you consider that taking the Ork metatype takes a minimum of C resources... how do you adjust for the lack of mental and emotional maturity? -20% skill points? -40% skill points.
Or, just hand wave it away?
And then there is the other players/character to consider. While every one loves their snowflakes, and wants special consider for their snowflakes, because their snowflake is just
that special, a tabletop game is still a social event requiring a social contract among the other players and GM... And some concepts are just taboo for some people.
"When you take a Snowflake and add it to other Snowflakes, you just end up with snow."