How did Bruce Banner end up with a son despite his earlier claims of infertility? Possible reasons explored

Bruce Banner, also known as The Hulk, is one of the most enthralling characters in Marvel Comics and the larger Marvel Cinematic Universe (MCU). While his role in the latter rendition of the Marvel Universe has shrunk since the Infinity Saga’s conclusion, he’s still reasonably involved, given current plans for the franchise’s future.

The most notable inclusion of Bruce Banner in recent MCU plans is in the She-Hulk show on Disney+. While the show didn't focus on him, his role as a supporting character was still crucial, especially concerning helping the titular heroine accommodate her new abilities.

One of Bruce Banner's most memorable appearances in She-Hulk came with the introduction of his son Skaar, who had been introduced in the comics some time ago. However, one of the most confusing points of Skaar’s introduction for many is Bruce’s earlier comments claiming he’s infertile and unable to have any children. Likewise, fans are curious to learn exactly how he ended up with a son, given these prior claims.

Origins of Bruce Banner’s son in the Marvel Cinematic Universe are still relatively murky

Unfortunately, She-Hulk doesn’t answer precisely how Bruce Banner was able to have a son despite his earlier claims of infertility in the MCU. While the Hulk's use of the word "son" and their similar appearances suggest Bruce Banner as his biological father, the Disney+ series doesn't explain how the alleged infertility is circumvented. As a result, there's unfortunately no straight answer on how Banner could have a son in the MCU.

Essentially, all that’s revealed is that Skaar was born in Sakaar and was 17-18 years old by 2025. While Skaar was only born 7 to 10 years beforehand, he grew to a comparable age of 17-18 due to time passing differently on Sakaar. Unfortunately, none of this helps to explain precisely how Banner was able to father a son, and no information has been released since that point has been clarified.

Skaar’s origins in the comics explained

Going off the Earth-616 line of comics, Skaar’s origins are thankfully made much more apparent in how Bruce Banner’s son came to be. Likewise, these comics' origins are expected to influence the MCU’s approach, with the film franchise likely to stick very close to these origins.

In the Earth-616 comics, Skaar is the son of the Hulk and Caeira the Oldstrong, a Shadow Person capable of using the “Old Power.” Caeira is a Sakaaran Shadow Person who first met the Hulk due to supervising his enslavement and training. She also found him and his rebel forces when he broke free from these shackles, but later sided with him when she realized her superiors had played her.

The two later married, and Caiera eventually gave birth to Skaar. Sadly, however, she died before his birth when the ship that brought Bruce Banner to Sakaar exploded. She and her unborn child were presumed dead, but it was eventually revealed she used her Old Power to protect him and several others, also trying to guide her now vengeful son.

How could the MCU explain Skaar’s existence?

With Banner’s claims of infertility currently being the most prominent problem in Skaar’s MCU introduction, his origins are expected to tie into Caiera’s and that of the Sakaaran Shadow People. One possibility is that procreation takes such a different form for the Sakaaran Shadow People that Bruce’s being infertile by Earthly and human standards is irrelevant to Skaar’s birth.

Another possibility is that Skaar is a reincarnated form of Caiera, achieved via the latter’s use of the MCU’s version of her Old Power. This would also pay homage to Skaar’s original origins, in which Caiera sacrifices herself to ensure his safety via the Old Power. The MCU has also been known to tweak storylines while paying slight respect to the original, so this approach seems incredibly likely.

One final Occam’s Razor-like possibility is that Bruce Banner either was never truly infertile, to begin with, or the Sakaarans found a way to cure his infertility. The latter approach would likely confirm Caiera as having helped him with this, hence his choosing to have a son with her. However, this MCU commentary is speculative as of this article’s writing, with the currently available information on the MCU’s Skaar severely lacking.