I've always loved Stardew Valley, and after moving to college I couldn't play because I don't have a laptop that supports steam—until the mobile app came out! I was very excited, but a little disappointed when I was making my character and male and female were the only options. I would love for a 3rd option to be added for gender (I would say "other" is fine although nonbinary would also work), with they/them pronouns and minor changes to the dialogue in the game so they're not referred to as specifically male or female. As for customization, the base sprite is already pretty neutral and there could just be a blend of the already available clothes and haircuts (assuming they even differ with the gender picked, because I haven't check). I love that Stardew Valley's romances are queer-friendly, and I think this would be a nice gesture to those that don't identify within the gender binary!
There is only 2 genders in white nationalist valley however, you can download the diversity mod and get maximum cultural enrichment you can get from this game. https://community.playstarbound.com/threads/diverse-stardewvalley-hiatus-im-dead.109748/
Sorry for digging up this old post. I searched "non-binary" in this forum, and I didn't see a lot of other posts like this, so I figured I'd come in and state how much I want a third gender option, too. Maybe keep the two body options (then again, there might not be a difference...) and then just add a "select your pronouns" thing? And regardless of gender, the sprites can have the same clothing options (if that's not how it is already, since I also haven't checked)?
Maybe the pronouns thing could work, but both could be implemented too...The model can stay the same since now there are more clothes at least on PC version rn. But, I did find it kind of annoying... Yes, the two can have the same clothes or air, but the NPC, still call you a girl or guy at the start at least.