I am currently working on a “Basic Youth” set for Genesis which will include both a teen girl and teen boy shape. These have been in development for a while now and so should be surfacing in about another month, just finalizing some of the extra included morphs and the new texture sets, of which there will be one each for the boy and for the girl.
The boy will look much more boyish than in the preview below—he just has a V4 texture in this image, because his isn’t finished yet, but this shows the basic shapes. These have all new joint parameters and any Genesis clothing will fit them perfectly.
You say Basic Youth. To me they look like Pre-Teen (10-12yo).
I would suggest you create 3 sets. Pre-Teen (10-12), Young Teen (13-16), Older Teen (17-19).
As well include a height/growth dial. Teens come in all height. Also head morph sets for these for variation. And for future you can consider texture sets for ethnic groups. I know my neighborhood looks like a rainbow.
Then it would have a range of age groups for those creating scenes for thing like say Harry Potter and other teen subject matter. I know I have considered making images for scenes from some of my favorite Fanfiction as a thankyou to the author. But found making a belivable teen with genesis is difficult. And like I mentioned before a height/growth dial would be useful. Using the Harry Potter reference as an example, Harry was short compared to his friend Ron. And the gap in height only got worse as they got older.
But the reason I suggest 3 set for age ranges is that faces change a lot for kids 10-19. You could easily include 10 age adjustment morphs for each of boys and girls for ages 10-19. So the 3 ranges I suggested are not that wild.
Anyway, hope to see this out soon. Ideally DAZ will simply come out with EVERY previous shape for genesis with autofit. So all those with previous collections of clothing for older shapes will be able to have those shapes in genesis.