Was Daria adopted?

Daria, who started out by being serenaded by Beavis and Butt-Head, "diarr-hea, cha-cha-cha"? Daria, who later got a spinoff of her own? Daria, who was called by one critic, "a 50-year-old deadpan Jewish comic in the body of a 16-year-old"? (We'll get back to that.) Daria, who perfectly personified teen agnst of the 1990s? (Oh, we know that angst so well!) Daria, who looked like this (picture on the left) and whose family looked like this (picture on the right)? She was adopted, right?

There is absolutely no way that brainy, sarcastic, inquisitive, caustic, brooding Daria was the biological child of her cheerily-vacant (WASPy) father Jake and her hyper-hustling (WASPy) mother Helen, or the biological sister of her brain-dead (WASPy) sister Quinn? She must have been adopted, right? Because — again — "a 50-year-old deadpan Jewish comic in the body of a 16-year-old"? That must be the explanation, right?

Apparently not...