To my knowledge, the subrace of planetouched races, particularly Tieflings, was originally hidden because such characters tend to veil their planar traits to avoid the stigma attached to them, and being easily recognized as a Tiefling could hamper such concepts.
Genasi however rarely obscure their ancestry - they are proud of their elemental bloodlines.
Still, examining them currently only reveals their base race.
Considering the predominantly very obvious elemental traits these characters display (Fire Genasi examples: "Charcoal gray or deep red skin. Red or orange hair that waves like flames. Eyes that glow brightly when the genasi is angry. [...] Large red teeth."), I think it might be worth adjusting this to reveal their actual, planetouched subrace if a lore check is passed.
Genasi however rarely obscure their ancestry - they are proud of their elemental bloodlines.
Still, examining them currently only reveals their base race.
Considering the predominantly very obvious elemental traits these characters display (Fire Genasi examples: "Charcoal gray or deep red skin. Red or orange hair that waves like flames. Eyes that glow brightly when the genasi is angry. [...] Large red teeth."), I think it might be worth adjusting this to reveal their actual, planetouched subrace if a lore check is passed.