Steven Universe is the child of Rose and Greg. In "The Guide to the Crystal Gems" Garnet refers to Steven as a fusion of love, much like herself.
In "We Need To Talk" at the end Rose and Greg dance as Greg attempts to fuse with before he kisses her passionately at the end.
The episode "Story For Steven" is about how Rose and Greg met.
In "Lion 3: Straight To Video" in Rose's video Rose and Greg are shown to have kissed at the end.
In "We Need to Talk" after singing their romantic duet "What Can I Do" together Rose kisses Greg goodbye.
In "We Need to Talk" after Rose and Greg speak they both spin one another around and laugh.
In "Story for Steven" Greg performs a song for Rose and when she tells him not to give up everything he wants, in response he declares, "You're everything I want!"
In "Laser Light Canon" after Steven activates the canon with Greg's mantra; "If every porkchop were perfect we wouldn't have hot dogs," Greg looks toward the canon's fire and says Rose as a tear trickles down his cheek, this shows how much she truly loved him using one of his phrases to make her magical weaponry work.
In both "Laser Light Canon" and "Maximum Capacity" a photo of Greg and Rose together is seen. The same photo is seen inside Lion's Mane in "Lion 3:Straight to Video."
In "Lion 3: Straight to Video" when Steven enters Lion's Mane, he finds a Mr. Universe shirt the same one Greg gave to Rose in "Story for Steven".