The way 5e is going, I think I’ll actually be embarrassed to teach a newbie. It would probably go something like this…
Newbie “ Wow, look at this one, a Minotaur, I want to play something big and strong like that”.
Me “Erm, well you can be strong but you’ll be just as strong as this one”
Newbie “What, that kid with the hairy feet, how does that work, I’m massive”
Me “Well, erm actually you aren’t, despite what it appears like in the these pictures and these plastic figures, you are actually the same height as a human, as is this small kid with the hairy feet.”
Newbie “Er, alright. I’ve seen Lord of the Rings. I want to be like Legolas, live hundreds of years. I’ll have pointy ears, I won’t be like this big, well not big, Minotaur thing, all clumsy, I’ll be really good with a bow”
Me “Well, the Minotaur is just as good with a bow, you can have pointy ears but you won’t live longer than anyone else”
Newbie “Ok, screw that, I’ll be a Dwarf and I’ll go kill lots of Orcs and Goblins”
Me “Well, although he’s called a Dwarf, they aren’t actually shorter than the average human. You shouldn’t really want to kill Orcs and Goblins either as they might be quite nice people actually when you get to know them.
Newbie “I’m not playing this stupid game”.
This is ridiculously stupid.
Newbie: Wow, look at this one, a Minotaur, I want to play something big and strong like that.
Me: Well, I was thinking about playing a halfling fighter as well.
Newbie: Aww, I really wanted to play something really strong.
Me: That's OK. I really want to be a fighter, but I can be a Dex-based fighter.
Newbie: Neat. How tall are Minotaurs anyway?
Me: The books say about 8 feet tall.
Bob: Heh, and I thought my 6'4" human was tall.
Newbie: Well, let's go kill some goblins.
Me: Hang on, are there goblins around here? I'm going to talk to the locals.
DM: Yeah, it turns out there's been some goblin bandits who have been raiding the local farms. They killed a farmer last week, too. There's a bounty on them because of that. Dead or alive, but it's the same amount either way.
Newbie: Wait, you mean we don't just kill goblins because they have a different skin color from us and our ugly according to my aesthetics?
Me: What? No, of course not. But these guys are bandits and murderers, so they're fair game.
So, you know, mature discussions and killing creatures based on their actions and not their race.