One Piece is a series that has been ongoing for a long time, and since its debut, the series has introduced fans to interesting lore and power-ups. However, one thing the show steers clear of is discussing family ties in more detail. Out of these main mysteries, one of the recurring plotlines is not revealing a character's mother.
From Luffy to Yamato, fans are fascinated to witness such powerful characters but gloss over their maternal lineage. One Piece does not introduce mothers, and this trait of the story has now become a running joke and a well of speculation among fans. The one that has been popular is the question about Gloriosa being Yamato’s mother. While there is no confirmation by Oda, fans have been talking about this in forums that it is a possibility she could be Yamato's mother.
It has been observed by many that Oda likes to give a dynamic introduction about fathers, but skips over mothers. For instance, we were introduced to Dragon as the father of Luffy, but it's been over 1000 chapters in the manga, and it seems that Oda has not even left a hint about who the mother could be.
That is why fans can’t help but speculate, especially when a beloved character like Yamato has such a glaring gap in their backstory. The reason why Gloriosa comes up when they talk about her potentially being Yamato’s mother is that she fits within the timeline.
Even if she is from the Amazon Lily tribe, she has left her tribe and returned years later. This is highly unusual for Amazon Lily, a place where men are forbidden and most women never leave unless they become pirates.

Because she decided to mysteriously leave, fans started speculating on her reason for the action. On the other hand, Yamato is around 28 years old since the time he was introduced in the Wano arc in One Piece. Some fans theorize that Gloriosa may have had a relationship or encounter with Kaido during her travels away from Amazon Lily.
Additionally, Oda is notorious for introducing characters early on and connecting them to the main story in shocking ways much later. Gloriosa introduced hundreds of chapters ago, might seem like a minor character, but so did Garp once upon a time.
While it’s never been confirmed, and likely never will, the point stands: fans are hungry for answers about parents, and One Piece gives them just enough crumbs to build wild (but sometimes shockingly accurate) theories.
The great One Piece mom mystery
Eiichiro Oda has an interesting aspect to his storytelling. In One Piece, fathers are either devoted or completely absent, but they are present in the story, unlike mothers. Fans have been asking, Where are all the moms?
Some maternal figures have appeared, such as Sora (Sanji’s mother) or Portgas D. Rouge (Ace’s mother), but they tend to be dead, absent, or only shown through flashbacks. Oda once stated in an SBS (fan Q&A column) that mothers bring a heavier emotional tone to the story, which doesn’t always fit the adventurous vibe he aims for.
It is noticed that whenever a mother is introduced, she is always of pure heart, and it is clear that he has nothing against introducing maternal characters. Oda has said he finds it difficult to portray mothers in a negative or morally gray light, and that is why he mostly prefers not to include them in a story where most of the characters live in a dog-eat-dog world.
Final thoughts
While fans love to speculate that Glorioso to be mother of Yamato, it has not been confirmed by the creator himself. If Oda chooses to connect the dots and reveal Gloriosa as Yamato’s mother, it would not only tie together two seemingly unrelated parts of the One Piece world but also offer a satisfying arc about women who defied expectations, suffered isolation, and returned stronger.