not here to argue any bc i def don't think that dirk/roxy and jane/jake r related to each other like. genetically obvs. i do think most people just like thinking that alpha mom n bro know theyre siblings or its bc theyre siblings, then that makes their adoptive siblings/children related by adoption. same w/ poppop and grandma in that they were adopted by the condesce and sassacre and technically r related by adoption, tho its looser bc grandma e did notable run away and was basically(?) disowned. again, not arguing with u at all. i just think ppl r leaning that their guardians r siblings or they were adopted into the same family and so they r related and thus its. tagged like that even tho its just the fandom heavily leaning into either headcanons or knowledge that isnt there (mom n bro thinking they're siblings, etc), and not the ectobiology front.
Yeah, I get where everyone's coming from on the sibling side of the headcanons, except that my takes are about Alpha Dirk and Roxy specifically, and they're definitely not related to each other, not even adopted siblings.
I have my own boundaries on Jane/Jake. From what I remember, they are adopted cousins, so you won't be seeing any of that from me personally.