Essentially, Steven Universe is a space opera about a half alien boy and his three alien caretakers, bent on defending the Earth. The aliens are gems that create essentially hollograms with mass, and from those gems they can produce specific weapons or change their appearance.
It's awesome imo, with a lot of action and cool backstory, but then again, it also has the SJW stigma. Since the aliens don't reproduce like we do, and can change appearence, it means that they choose to look like female humans. This is what gets the Tumblerinas salivating. But that's only a minor tidbit about the aliens' backstory. I don't think they ever talk about it on the show in the first place. It also looks dumb on the surface because Cartoon Network likes advertising things "lel so random funny" now, rather than showing any action or the parts that are simply disturbing.
If he starts talking about gender identities or so much utters the word "cis," then you can disown him or whatever you claim, because that's the stereotype people seem to hate. Otherwise, leave him alone. It's a good show if you disregard the more rabid SJW fanbase.
