Goku’s Mother is Selypa
Selypa being Goku’s mother — a rumor massively prevalent pre-2014 (see below!) — is pure speculation. Perhaps the biggest piece of damning evidence is in the television special itself when Selpya asks Bardock if he just had a son. Were Selypa actually the mother of “Kakarrot”, there would be zero reason for her to ask this question in the first place. Additionally, one would think that if she were Goku’s mother, she would have gone with Bardock when he went to see him in the hospital complex, or perhaps even still have been in there from the process of childbirth!
As with most characters in Dragon Ball, no mention of Goku’s mother is ever made in the series-proper, and there is no evidence what-so-ever that Selypa was the mother. This had been the topic of many dōjinshi and fan-fiction, however; a common name for Goku’s mother in older fan-fiction was a variation on “Turnip”.
The Saiyan overview from the Dragon Ball Z Movie 7 “Film Anime Comic” clears things up quite well, showing no relation of Selypa to anyone other than Bardock, and only in a subordinate (buka) relationship along with her other three crew mates.
In the March 2014 issue of Saikyō Jump in Japan, a “Super Q&A” between Dragon Ball SD‘s Naho Ooishi and Akira Toriyama brought to light a new tidbit of information: Toriyama had created a new character — named “Gine” (a pun on “negi” or “spring onion”) — to serve as Goku’s mother!
Gine debuted in the bonus “Dragon Ball Minus” chapter within the collected edition of Jaco the Galactic Patrolman released 04 April 2014 in Japan.
Gine later appeared — adapted roughly as-is from “Dragon Ball Minus” — in the 2018 theatrical film Dragon Ball Super: Broly. Gine has also made appearances in various video games, including Dragon Ball Z: Extreme Butoden, Dragon Ball Fusions, and Super Dragon Ball Heroes.
