Now that DC Comics has decided to put Booster Gold and Harley Quinn together in her solo comic, fans of both characters are wary of the fallout from the matchup. For Harley, her romance with Poison Ivy, which had been cultivated (no pun intended) for years, appears dead in the water, as a result of Heroes in Crisis and/or the Harley and Ivy miniseries and/or editorial meddling. That relationship, which is canon now on the Harley Quinn animated series, will probably come back around in the comics soon enough. But for Booster, there's a potentially longer-lasting effect of his romance with Harley.
That is, an older, future version of Booster Gold once revealed that he has a son. In fact, his son is Rip Hunter who, because of the magic of time-travel, is one of Booster's mentors in the whole Time Masters business. So, as with any woman who enters into a relationship with Booster, we have to ask: does this mean Harley could be Rip Hunter's mom?
For the uninitiated: During the second volume of Booster Gold, which launched out of the events of 52, Rip Hunter was revealed to be Booster Gold's son...but the identity of his mother remained secret. She was referenced often during the next fifty or so issues of Booster Gold, Time Masters: Vanishing Point and other titles featuring the characters, but never named, and few hints were even given.
One popular theory is that Rip's mother might be Alexandra Gianopoulos, a Greek heiress Booster first encountered on the Flashpoint Earth, whose mind or soul or something appeared to make its way over to the Vanishing Point after Booster and Skeets left that world. A woman resembling Gianopoulos appeared on the initial, solicited cover of Justice League International #1 in the New 52, but she was later replaced by Godiva. Because of this switcheroo, and some minor flirtation between the characters during the book's run, some fans also guessed that Godiva might be Rip's mom.
"I’ve been around long enough where edicts have been issued that say universes die, no more time travel, but oh wait now we can...and I just think characters live on in a way," Jurgens told ComicBook.com five years ago, when asked why he hadn't simply revealed his plans on Twitter or something. "Certainly with Convergence, what we did is we sort of tweaked Booster Gold's origin and we also showed what happened to Booster Gold from the pre-Flashpoint universe....I always look at it and say there’s going to be a chance one day, someday somehow, to give those answers."
All of that said -- could Harley Quinn really be the mother of Rip Hunter?
Almost certainly not.
Even if the Harley Quinn series did not often appear to exist in its own reality where ties to DC continuity are tenuous, it's plausible, if not likely, that the Batman office and the Harley Quinn creative team don't even know about Rip Hunter's parentage or that Booster has a kid. Besides Jurgens, who created Booster, and Geoff Johns, who wrote the Rip Hunter twist during his run on the comic, few other creators at DC seem to pay any attention to the mythology of Booster, opting instead to see him as an ineffectual boob, an impression created by the Keith Giffen/J.M. DeMatteis Justice League books of the late '80s and early '90s. In the Booster Gold comics by Johns and Jurgens, that notion of Booster being a dimwit is something the character fosters in order to reduce the odds that a time-traveling villain will try to murder him as a baby or something like that. So, basically, most DC writers aren't writing Booster Gold as presented by Johns, Jurgens, et. al. They're writing Booster as his own cover story.
The handful of flashbacks to Rip's childhood that happened in Booster Gold and Time Masters: Vanishing Point never mentioned anything about his mother being a major DC heroine. Obviously that would not necessarily have to be brought up, but in Time Masters, rescuing Batman was a big part of their mission. At that point, Harley was mostly still associated with The Joker, which feels like it might have come up.
Obviously that's all speculation, since nobody at DC knew that they would ever experiment with Harley and Booster as potential romantic partners. Still, on the off chance the Harley team had any plans to address Booster's future, it seems like they would also be aware that there was nothing to support the notion that Rip's mom is Harley.
You might get something resembling a real answer in Batman Beyond. In that series, written by Jurgens, Booster is making an appearance this fall -- and it seems like a trip to 25ish years in the future is a perfect opportunity to at least tease something on that front.