None of the considerations about what DC does would answer why someone would think it’s okay for other Marvel heroes to marry and have children, but not Marvel’s biggest character. As Spider-Man is the company’s flagship character, and so important to the shared Marvel Universe, there will be unique restrictions to the series. But let’s see how writers of the other Marvel franchises have dealt with superheroes gettng older and having families.
Kids From the Future
Rachel Grey and Nate Summers in the X‑men books, have sometimes been used as examples of successful children of major superheroes. Rachel is the future daughter of Cyclops and Phoenix, while Cable is the son of Cyclops and a clone of Jean Grey, sent to the future as an infant at the age of one, before he returned as a middle aged man. So these aren’t exactly typical offspring.
It’s more obvious when an infant or young child becomes an year older (or fails to become noticeably older, when the adventures have clearly been going on for a while) than when a 21 or 54 year old from the future does. The kid from the future cliche could work with any character, so there’s no reason it has to be Spider-Man. For example, it might be fun to try it with a future-born offspring of Franklin Richards. In addition, the relationship between Cyclops and Phoenix is more convoluted than anything we want the Spider-Man books to resemble and the origins of Cable and Jean Grey don’t help.
Black Panther and Storm
Black Panther and Storm’s marriage occurred under Quesada’s watch, so many suggested that it was hypocritical for him to support it while trying to undo the Spider‑Man marriage. However, Peter Parker is their flagship character, while Storm is part of an ensemble and Black Panther has one solo title—and often no solo titles—meaning that their private lives just aren’t as important as Spider-Man’s.
Black Panther’s first appearances in Fantastic Four, Captain America and The Avengers made no notice of his marital status, and Storm’s romances were also an insignificant part of the X‑Men for the first few Essential X‑men volumes. Nightcrawler had a crush on her in the early issues, and Doctor Doom flirted with her in her 50th issue of the X‑Men, and I think that was it. Peter Parker got shot down by a girl on the second page of Amazing Fantasy #15 so his bad luck with women was established in his first appearance and has been a major part of the character’s appeal since then.
Most of T’Challa and Ororo’s earliest stories wouldn’t have been altered by the revelation that they had a spouse their teammates never met. In marrying the two, Marvel also provided a link between the Black Panther (and his comrades in the Fantastic Four and the Avengers) and the X‑Men franchises, permitting new stories for some of their biggest franchises. Joining Peter and Mary Jane provided no such advantage.
Their relationship was also established in an early Marvel Team-Up story by Chris Claremont and John Byrne, so it did come with a high pedigree.
Luke Cage and Jessica Jones
Another relatively recent Marvel marriage (this one included a kid) was the one between Luke Cage and Jessica Jones. Cage hasn’t had a solo series for a while, and Bendis decided that Jessica Jones’s solo adventures were over after writing 28 issues of the character in Alias. The Spider‑Man writers don’t have that luxury.
Bendis was able to have Jessica Jones and Luke Cage become a part of the ensemble in The Pulse and New Avengers, which is why he was able to make their private life more stable. Neither has a monthly book (or three) to support for an indefinite period of time, and because of their edgier origins (Jessica Jones was created as the star of a Mature Readers title, and Luke Cage was always meant to have street cred) Bendis and other writers are free to explore complications you just can’t do with Spider‑Man, such as infidelity. If Luke Cage and Jessica Jones were to get a divorce, there’s a very slim chance of it being a major story on CNN. Bendis is also able to play around with the possibility that their marriage will come to an abrupt end, as he did in New Avengers #38. And later writers can move them off the Avengers, to focus on their own pet characters.
The Fantastic Four
Many have compared Peter and Mary Jane to the first couple in the Marvel Universe: Reed and Sue Richards. There are several reasons why someone could believe that Mister Fantastic and the Invisible Woman can be married with children in the comics, and Peter Parker shouldn’t. Reed and Sue have been together since the first issue of The Fantastic Four, and the writer and artist of that issue created the stories in which they got engaged, got married, found out that they were expecting a child, and had a son. This all occurred long before Stan Lee realized that the Marvel books would be around for a while, and decided that the illusion of change was more important than actual change.
Franklin Richards hasn’t really aged much since the beginning of Byrne’s run, and with the exception of the addition of Valeria Richards and the formation of the Future Foundation, the status quo of the series has remained ultimately consistent. Johnny Storm died, but he came back. He married Ben Grimm’s ex-girlfriend, but she was really a Skrull in disguise, so he was back to his old self soon enough.
The Fantastic Four has always been about a superhero family, so kids are simply another part of that core premise. Marriage and children also change the storytelling opportunities less for the series, as Reed and Sue are just part of an ensemble. It would be entirely plausible for Johnny Storm or Ben Grimm to get married and have families, but that’s not a direction the writers prefer to explore. The other two members simply gain a nephew or niece with each new Richards kid. The writers are thus free to do the soap opera elements which require the heroes to be single with the Thing and the Human Torch (or any of the substitute Fantastic Four members.) Plus, Reed and Sue aren’t even always part of the Fantastic Four, which allows the writers more flexibility in handling the private lives of the team members.
Other Characters and Kids
Other Marvel heroes have been married and had kids, but this rarely encourages a similar approach for Spider-Man. Wolverine’s much older, so adult children are credible. Scott Lang, the second Antman, was a single father, but that was one of the things that distinguished the B-list character. Matt Murdoch’s marriage to Milia Donovan was annulled, and their relationship ended badly. It was fitting for a character with a chaotic back-story, a blind lawyer who no one pretends is supposed to be the everyman.