Board Thread:Naruto Discussions/@comment-30642680-20161130150600/@comment-734582-20161201153344

BakumatsuWarrior wrote: Kaguya is an alien, whose eggs can somehow be fertilized by a fertile human male. It has been confirmed that she's an alien. Her ability to enjoy the sensation of a human male's member inside of her, and the consequent act of her giving birth to two half-human hybrids, doesn't detract from her pure alien origins. Considering that these aliens are still human-like, i don't know what deeper theory exists to explain that (panspermia? Creator deities?), but i think that Kaguya's alien status reflects more the fact that she comes from another planet than that she's wildly differently from actual humans.

So in a sense, she's a human-esque alien with some different qualities (e.g. it seems Otsutsuki possess white eyes and white-ish skin) but she's pretty much genetically human. Her origin however is alien.