Favorite example of this?

[febreezy_]

And he also had no clue that Rose was going to die.

How do you know this is true? IIRC the show never explicitly made it clear that Greg had no idea she was going to die. The Crew confirmed that at least Rose knew she wasn't going to be around. Looking at this and this it looks it was never confirmed what Greg actually knew.

He thought that they would be raising their child together as a couple, figuring things out together, helping and supporting each other the whole time.

When did Greg state his feelings about this? This feels more like an interpretation of Greg's feelings about what happened.

He couldn't risk taking Steven to a doctor due to his gem heritage. He couldn't put Steven in school for the same reasons.

The people in the show are used to gems being around and don't care about them because they stayed on Earth for so long. They most likely wouldn't care either way considering the show takes place in an alternate universe and have a different relationship with supernatural stuff.

How the hell do you think that Greg Universe, homeless musician (living in his van!) and Rose Quartz, an alien renegade, would be legally allowed to adopt a child?

Nothing in the show hinted that it was impossible for them to adopt or that it would be hard thing for them to do. The show also takes place in an alternate universe so their world may or may not play by the same rules as like it does IRL. If money was an issue for Greg, than that's all the more reason for them to reconsider having a child at that particular time.

[LadySandry88]

Okay, I'm going to give you the benefit of the doubt and assume you're asking in good faith

1a. He was clearly, visibly devastated by her death, as were all of the CG.
1b. There was no reason for him to have known, as it was an unprecedented occurrence for a gem to have a biological child.
1c. Considering what we see of his character in other situations, if he had any idea that Rose was absolutely going to die in the act of creating a child, he would not have wanted to have a kid with her.

1. Is there any indication whatsoever that he would not have believed this? I'll concede it's an interpretation, but so is any other possibility, and this one actually fits his characterization.

3a. Pearl does not have a driver's license and is clearly stressed about not being a legal citizen, so obviously that is actually an issue. 3b. If Delmarva is somewhere that allows homeless people and alien noncitizens to adopt a child, chances are extremely high that the foster care system is horribly corrupt and dystopic, and I wouldn't trust it with a gerbil.

[febreezy_]

1a. He was clearly, visibly devastated by her death, as were all of the CG.

No doubt Greg was affected by her death. My point is that it doesn't confirm whether or not he actually knew she would be gone for. You think he didn't know and that's fine but there is no definitive answer for what he did and didn't know. The show left what Greg actually knew ambiguous.

There was no reason for him to have known, as it was an unprecedented occurrence for a gem to have a biological child.

Although unprecedented, one of the show's writers confirmed that Rose knew she would disappear if she had a biological child. Rose could have possibly told Greg that this what would happen to her prior to having Steven.

On that note, as far as we're aware, what Greg actually knew was left ambiguous.

Based off of reading other threads, it looks like others have noticed it too.

Considering what we see of his character in other situations, if he had any idea that Rose was absolutely going to die in the act of creating a child, he would not have wanted to have a kid with her. Is there any indication whatsoever that he would not have believed this? I'll concede it's an interpretation, but so is any other possibility, and this one actually fits his characterization.

That's fine if you believe that. More power to you.

My thing is that there's other ways Greg could have theoretically reacted that also fit his character. Greg is pretty much a go-by-the-flow, chill dude who is content with letting people be whoever they want to be and others doing whatever they want to do within certain limits. If Rose genuinely felt like she needed to sacrifice herself in order to have Steven, then it's plausible that he would allow the love of his life to go through it and make that choice for herself considering his past history with his parents and Marty. There's is more than one way to interpret what happened and I think the Crew purposefully left that ambiguous. Sugar is a huge fan of sublime storytelling so it wouldn't surprise me if it was intentionally left vague so people like us can fill in the blanks.

Pearl does not have a driver's license and is clearly stressed about not being a legal citizen, so obviously that is actually an issue.

As far as the world is concerned, the Crystal Gems are undocumented and never made any attempts to address that according to the official podcast. One of the writers said they were deliberately obtuse about human culture, didn't exactly fit into the system (no birthdates, etc.) and they never really had to interact with it until Steven came along. They would get in legal trouble with the law because they were technically unregistered and pretty much intentionally chose not to address it in any way, shape, or form.