Gogo and Didi are aliens that look human.
- Didi spawned from Gogo which means Gogo can reproduce asexually. Also humans don't bud off one-another like that. Yet they think it's completely normal and don't understand why everyone else is so freaked out.
- We don't know their parents. Whose to say they're even from Earth? Or that they even have two parents for that matter considering the information above?
- Didi and Gogo, especially Gogo, are weird. Different species have different psychology and behaviors.
- Gogo can lift and throw a truck when she's angry. Now, the human body can do some pretty amazing things under extremely stressful situations including Unstoppable Rages. But it only uses its full strength/speed/etc. under extreme circumstances because it puts a lot of strain on the human body. She not only does she lift and throw cars, but she does it frequently. To the point, where when Didi calls her a "[...] Womanchild who throws trucks when she's angry", Gogo's only defense is that she sometimes throws regular cars.
- Gogo is a pretty weird name for a human.
- Gogo has a pair of robotic gloves. Aliens are usually portrayed as more technologically advanced than humans.
- Gogo and Didi have yellow eyes. Now the in-series explanation is that she mutated as a result of radiation or a plague. But they go on to say she was the only victim (which is in quotes) and at most, it says "At the time, the "golden eye" was thought to be symptomatic of radioactivity or the plague." meaning it's possible that people just assumed that it was some freak mutation or disease. But Hector is seen dating a girl with purple eyes and hair. So it's possible it's just an aesthetic choice.
- Instead of Christmas, Gogo and Didi celebrate Gerexomas, a holiday celebrating the birth of a Stellar dragon named Gerexon. It's possible that it's a holiday celebrated by a small (fictional) religious group from Earth. But it also could be an alien version of Christmas.
- Gogo tries to find Didi and she meets a Vulcan. This means either one of two things: 1) she traveled to another planet or 2) aliens have come to Earth before. Either way, traveling to another planet in a short amount of time is possible in this universe. Or they could be aging slower than normally and as we all know, different species age at different rates.
- That blue Cartoon Creature, Pablo, could be another alien they took with them. Didi did say there isn't another member of his species within miles. He also can text, albeit in an almost unreadable fashion (almost like he needs to sound the words as he spells it).
- Andy once told Gogo that "[he knows] that [she's] not... a human being." He probably means that she has inhuman abilities and nothing more, but even then it still could be foreshadowing her origin.
Gogo's odd and unstable number of limbs and other physical oddities during childhood was a result of Didi being present all along.Things stablished when Didi started to separate out, then eventually Gogo was able to spawn/bud/whatever once Didi reached a certain stage. This also explains the relationship - Gogo isn't Didi's mother, but closer to a Siamese twin post-separation.