She shapeshifted in order to give herself a womb. Had a pregnancy with Greg as the father. Bequeathed her gem to the baby at some point.
The crewniverse have said that Rose shapeshifted a womb for Steven. Nothing more, nothing less. Any other explanation on how Steven was created is up to your discretion and imagination.
So as we all know the canonical explanation for how Rose got pregnant despite being (technically) genderless was by shape-shifting an entire female reproductive system.
Q. Are the twins actual twins? Yes, they were both conceived by Greg and Rose without Pearl's involvement. Rose was pregnant with them both.
As a gem, Rose Quartz couldn't have a child with her human partner in a traditional sense and ultimately had to give up her physical form for Steven to be born.
He is the first and only known Gem–human hybrid, the product of the union between the Crystal Gems' original leader, Rose Quartz, and Greg Universe, a human musician and car-wash owner. Rose "gave up her physical form" to create Steven, leaving behind only her pink, pentagonal-faceted gem, now embedded in his navel.
Steven's gem glows when he's comfortable and surrounded by his family's love, just like in the first episode. Amethyst shapeshifts into a baby, something she does again in "So Many Birthdays". We see Buck and Jenny as kids, playing in the snow.
Initially, I thought Amethyst had repressed romantic feelings towards Greg and was slightly jealous of Rose's and Greg's relationship, but I see now that this isn't the case. Pearl said that Amethyst and Greg would be gone for days. This would indicate that Amethyst and Greg were really close at one point in time.
Did Jack and Rose from the Titanic have a child? No, Rose married after Jack's death and had a child. Rose's adult granddaughter is with old Rose in the beginning and end of the movie.
According to Vrai Kaiser of The Mary Sue, Pearl deals with severe unresolved grief, coupled with deep-seated issues with self-worth, resulting in her falling prey to "powerful, impulsive emotions" whenever Rose is mentioned. Naith Payton of PinkNews described Pearl's devotion to Rose as "unhealthy and obsessive".
There are dozens of examples in the show that hint at the idea that Rose Quartz wasn't exactly a great role model, least of which was the revelation that she was actually Pink Diamond, one of four evil space queens whose imperial motives terraformed thousands of planets across the galaxy, but even as Steven learned ...
Pearl love Rose and was jealous at Greg because she see him as her rival. In The Message, After Greg fails to get Wailing Stone work, She disrespected him and say "What a waste of time" and she didn't even say thank you to Greg after he finally get Wailing Stone work! I wonder if she will be not sad that Greg dies!
It has been confirmed by Rebecca Sugar that Gems don't naturally reproduce and lack reproductive organs.
Steven remembers she's not his real mom, she's just been acting how he wants her. He doesn't even know if this is how she really is. He'd learned things about her, how she wants to keep things secret, like how she locked Bismuth away (due to her wish to shatter gems) without telling Pearl or Garnet.
Can Steven have babies? In nature, most hybrids can't have babies. Plus, half of his DNA is on the gemstone, so if he passed it to his kid he would just become a Greg clone (Since without Rose's DNA, which is on the gemstone, Steven has only Greg's DNA).
Additionally, Smoky Quartz, a fusion of Steven Universe and fellow Crystal Gem Amethyst, is nonbinary since, as series creator Rebecca Sugar stated, the Gems are "all non-binary women," which applies to Amethyst specifically.
Rainbow 2.0 is not male, he uses he/him they/them pronouns, but technically speaking they cannot be male.
Prasiolite (also known as green quartz, green amethyst or vermarine) is a green variety of quartz.
If Steven and Connie had a baby it would not be named Stevonnie and it would be male, female, or intersex. Stevonnie is a combination of Steven and Connie. Any child of their would be a different human entirely, and should not be defined as a person by who Steven and Connie are.
The answer, it turns out, is that he would need to reform: Once White Diamond pulls out his Gem in an effort to revive Pink Diamond, Steven is left deadly ill, while the Gem goes through the stages of its own evolution from Pink to Rose Quartz to Steven.
Steven throws up Rose's hair in his nightmare, indicating he needs to let go of his desire to live up to Rose's legacy; he feels overwhelmed by having to deal with Pink's responsibilities.
Steven's own expression of his gender identity is one that has not traditionally been offered for males. Steven is the only gem who is male, and this is likely because he is half-human.
Pink technically did fuse with Greg when creating their son Steven (since Steven got his Gem half from Pink and his organic half from Greg). After Greg found out "Rose" was Pink Diamond in the episode "The Question", he admitted that her former identity didn't change his feelings towards her.