I think Hussie mentioned smthg (b4 we meet the alpha kids) about all the human girls' chumhandles being 2 identical letters to represent the XX chromosomes but Roxy is the only human girl not following this rule so she could b trans

Sadly, that’s a genetic mix-up, what he said was that all the Humans and Troll handles are made up with the 4 DNA letters, GCAT. That being said, Roxy and Dave, popularly headcanoned trans, are both [TG], and Roxy and Dirk break the pattern of human girls having the same letters [TT, GG, GG, TG], and the boys having different letters [EB/GT,TG,GT,TT].