Do your human pcs tend to look like you?
No. Most are younger. All are better looking, & in much better shape than I'm in (or have ever been). Those who're older are along the lines of what I wish I'd look like, but will not achieve - for starters not of them are balding.
Do they usually match your;
ethnicity: Yes, assuming "some degree of Caucasian" counts.
sex: Yes - Other than when DMing I've never made a female human.
gender: Yes
sexual preference: Yes
How often do you play characters who don't? Feel free to include non-D&D human characters in your discussion.
Other than when DMing, in this century, I've only got 3.5* Female characters of any type in any system.
2 Halflings (a Warlock & a Barbarian), 1 Tiefling (a PF Divination Wizard), & 1 1/2elf(?) Sorcerer(?)Warlock(?)Sorlock(?)* All 4 are female hetero.
The 1/2elf only counts as .5 of a character atm because she's a concept waiting for the right D&D/PF game. Mechanically she's a 1/2elf but doesn't have stats yet & her class isn't set beyond
"caster, not a Cleric/Druid/Wizard". Sorcerer will probably end up the best fit. The hard parts done though - I know who this character is, what makes them tick, & (generically) why they've taken up the adventuring life. I even have a mini.
The last 5 characters I've played;
Current - Bree Burrfoot: Female Halfling chainpact Warlock 5e (or Summoner in PF1). Caucasian. Hetero (though NA)
Current - Jack'son: Male Human Rogue. Caucasian, Hetero (though it's not likely to matter)
Zarbag: Male Goblin Sorcerer (PF2). Green skin & based on Night Goblins/Moon Clan Gitz from Warhammer if that means anything to you. Hetero, but it never came up.
Gojira: Male Dragonborn Paladin (5e). Green DB, though he breathed fire. Hetero, but NA
Karzouk, the Almighty: Male 1/2elf (mechanically) Transmutation Wizard (5e/PF). Varisian, so Caucasian-
ish. Played as though he were a human. Hetero, though it never came up.