The Big Question We Still Have About Aang's Origin In Avatar: The Last Airbender
As far as young heroes go, "Avatar: The Last Airbender's" Aang is one of the most heroic. Just, wise beyond his years, and defiantly kind, he's exactly the sort of hero parents would hope their children would admire (aside from the rampant property damage, of course). Aang's worldview is entirely informed by his life in the Southern Air Temple, where he was raised by the Air Nomads — a group of airbending monks who idealize pacifism, balance, and selflessness.
The Nomads were eventually wiped out by the Fire Nation, attempting to kill the next Avatar before they could be trained. Fortunately, Aang had already run away from the Southern Air Temple by that point. He ultimately was frozen in an iceberg for the next 100 years. Despite being the show's main protagonist, shockingly little is known about his early life. While the series briefly touches upon his time with his caretaker, Monk Gyatzo, they peculiarly never address his parents and what became of them after his birth — or if he ever had them at all.
Did Aang have biological parents?
Given the show's lack of cloning technology or other means of immaculate conception, it can be said with almost 100% certainty that Aang had a biological mother and father — they just may have not been a familial mother and father. Aang is a member of the Air Nomad tribe, a community of monks who lived in the four Air Temples (north, south, east, and west). As Screenrant notes, "Avatar" and its sequels were loosely inspired by different historical cultures throughout the continent of Asia.
The Air Nomads were primarily inspired by Tibetan monks, who in reality would take a vow of celibacy upon joining the religion (via Learn Religions). This creates a bit of a conundrum for the show and how its rules work. Though at first glance it appears as though the Air Nomads are chaste, the ultimate answer is far more complicated and rooted in the show's mystical lore — the only way Aang could have his awesome, terrifying powers is through his biological parents.
What happened to Aang's parents?
In "Avatar: The Last Airbender," a character is almost always granted the gift of bending because their parents are benders themselves. While it's possible for bending to skip a generation (in the case of Toph Beifong, whose parents were non-benders) or for bending parents to have a non-bending child, the lineage of a character determines the specific type of bending they have. For example, if Toph were ever going to have bending skill, she would either be an earthbender or nothing at all, as that's what's in her bloodline. There was never a chance of her becoming a water, earth, or firebender. When the Fire Nation eradicated all of the Air Nomads, it turned Aang into the titular "Last Airbender," as there were no Air Nomads remaining to have airbending children.
Because of this in-universe law of nature, Aang must have had at least one Air Nomad parent, and — given how many Air Nomads there once were — it's likely every Air Nomad had parents in the monastery system as well (a direct contradiction to their Tibetan predecessors). That being said, because of how common it was in their culture, it's likely Nomads simply deemphasized parental relationships to avoid attachment to earthly people and possessions. Aang was probably separated from his parents at birth as a matter of custom. From there, of course, he would be raised by Monk Gyatzo until his eventual (fatefully permanent) departure from his Air Nomad family.