No, this isn't something as monumental as the Captain America twist that happened in his first issue. Also, I don't believe that Marvel backtracked because of angry fans. Any who, back in 2013, in Iron Man #17, it was revealed that Tony's biological parents weren't Howard and Maria Stark – but two complete different individuals.
He also met their real son, Arno Stark, as well. Honestly, I love twists like this. This is what makes reading comic books so freaking amazing. Y'see, comic books are always coming out, and this affords the writers the opportunities to do whatever they like! And I know, some people don't like how they can just retcon a certain situation and be done with it. I don't mind.
Now, it has to be a huge reveal. It can't just be someone that we've never met. That won't break the internet, like the Captain America's twist. I was reading Newsarama, and they had an awesome theory! Honestly, it makes sense, and it's guaranteed to get people talking!
Lady In Red
That's right, Natasha Romanov a.k.a Black Widow, is most likely Tony's mother. And if you're an avid comic book fan, then you're probably thinking of a sex tape right now! I'm not a perv, but that's the first thing I thought when I read this. In the late, great Ultimate Universe -- Tony and Natasha made a sex tape together. But don't worry, as far as I can tell they'd never slept together in the main continuity.
The comics' version of Natasha Romanov has more in common with Steve and Bucky, then probably any of the other Avengers. You remember her training in Age of Ultron? Well, same basic principle, but add a few enhancements, and some years. Now, you have the comics' version of Black Widow!
And yes, I'm also insinuating that The Winter Soldier is Tony's father. In Captain America: Civil War, when Bucky slammed Black Widow on that table, she said something reminiscent of a past flame. Now, I could be wrong, but that was the impression that I got from the encounter.
Plus, it's kinda poetic that Bucky killed Tony's parents -- while also being his parent. This would be interesting. Lastly, I know I'm mixing mediums, but oftentimes you can look at the movies for inspiration for the comics.
You never know what Marvel is thinking when it comes to their vast number of characters. This theory could be totally wrong, but I think it would be extremely interesting to see this come to fruition. Even though, in hindsight, I'm sure some of the comics might be a little weird now! I would love to know what you think. Should The Winter Solider and Black Widow be Tony's biological parents?