In a sense, the replicants in Solar Opposites, Jessie (Mary Mack) and Yumyulack (Sean Giambrone) are children. They go to school, they refer to each other as brother and sister, and Jessie is pretty excited to be able to have school girl crushes.
In a way, Terry and Korvo are their parents. Though the whole family are out as aliens in the town they crash-landed in, they adapt into a typical suburban family. They essentially treat the replicants as their children.
That being said, the two heads of the family don’t appear to be in a romantic relationship, at least not throughout the eight episodes of Season 1. Essentially, it’s kind of like an animated alien version of The Odd Couple. They’re two grown “men” who are roommates with polar opposite personalities. As far as being a gay couple, it doesn’t seem like they have something beyond a platonic relationship. It’s clear, over time, that the whole family loves each other, though.
In fact, we hear Terry call Korvo, “My Korvy”, which hints at the fact that he does love his partner. But we’ll have to wait and see if that love becomes a romantic love in later seasons, which, by the way, it’s already been renewed for.