This is already to some degree an existing dilemma. There are already individuals out there who, due to genetic lottery, happen to have an adult body that through some efforts of clothing, makeup, hairstyle, etc, can very much present themselves as substantially younger looking than their actual age.

Lord knows certain popular niches in the porn industry make this apparant... >_>;

And from what I have heard on social media, sometimes these individuals couple up with another person who... doesnt look substantially younger.

And often, these couples face quite a bit of controversy and social stigma, despite everything they are doing and into being 100% legal and, from am objective standpoint, ethically fine (they are two consenting adults after all)

But I agree that future tech with things like gene editing and whatnot this dilemma will certainly become substantially more pronounced and I think it will likely be yet another group being attacked for daring to live their lives.

I can't imagine there would be that many people who would want to look like an actual child. 20-ish, maybe, but not 12. Think about it. You'd have trouble keeping a job because no one would take you seriously. You'd probably get harassed by cops if you tried to drive anywhere. Everyone would treat you like you have no experience or knowledge.

Trust me, I am one of those people who looks 10-15 years younger than I am. I don't look nearly as young as 12, but I still do not enjoy looking young. I often feel alienated from my age group because they don't see me as one of them until they find out my age.

I have a friend who is in her 30s and is 4'11. She looks like an adult woman, just a small one. Her bf is average height. He gets a lot of dirty looks when they are affectionate in public.

Japanese ~~philosophers~~ mangakas seem to have already popularised thought experiments on it

I would imagine there would eventually be legislation to not let people cosplay under the age of consent with this new tech.