Sure, been doing this for 3-4 decades of roleplaying. Before that it would be one player running a whole party, so while there may be things marked down on the character sheet, there wasn't a lot of RP for it to come up. But the first long term, deep RP game I got into didn't care and it was the normal so it never seemed odd. Yeah, some issues with teenaged boys (the girls were fine) but that got weeded out quickly. We had characters in relationships with both PCs and NPCs, including marriages and eventually kids. I think it helped that the same extended group of people also played Champions together, and there was a lot of soap opera in that game. Heck, I remember playing a (tastefully) gay elf back in the late '80s - and that wass unknown territory. Everyone around the table thought it was great when it came out and "very elf-y", laughing or commiserating with the wizardess who had a crush on my character since she was introduced.
Recently I was playing a transhuman game with resleeving into different bodies, and one of the topics I explored was changing gender in various ways and the acceptance or not of it, both by others and by the self.
One of the games I run for has several non-binary players, and some non-binary characters - and don't think that the PCs and the players match. Including "Rin has no pronouns, just 'Rin'". I couldn't possibly think about trying to police gender in that game.
As a side note, every DM does this all the time with NPCs. How can it be an issue when players do it?