"True enough."

"So can any two people have kids together without magical help where you're from, or just certain matchups...?"

"...No, of course not. Any desi can get someone pregnant, and any hari can get pregnant, but--wow, I was not expecting to have to tell someone about the swans and the minnows today. A desret can get anyone pregnant who can get pregnant, which is all three hari genders and also desmi. A harret can only get pregnant by a desret or another harret and can get anyone pregnant who can get pregnant. A desan can get a haran or a harmi pregnant. A desmi can get a harmi or another desmi pregnant. Haran and harmi can't get anyone pregnant. Um, have I forgotten anything."

"...I don't know, I completely lost track of that halfway through and may need a chart."

"...Bar, can I have paper and a pencil please?"

If you borrow a whiteboard and marker instead I won't have to add it to your tab.

"What are those?"

Behold!

"Ooh, nice. Do you have more marker colors?"

Here is an array of them.

She selects the black and the green and the red, and makes a chart

"Huh. Okay. So... why can't the four combinations that don't work, work?"

"I don't know, they just don't."

"Huh."

"I wonder how two-gendered people fit into it," she muses, tapping the green marker she was last using against her chin. "Maybe you're too different from us just on account of the genders thing, or maybe your genders aren't compatible, or maybe one of your world's desi could sire a child on someone like me."

"No idea. I mean, if nothing, else, even on my world two people who couldn't normally have kids can do it with magic."

"Really? How?

"...A wizard does it? I don't know the technical details. You need a woman around to carry the kids, usually one of the moms if it's two women or like an aunt if it's two guys."

"I wish my world had magic."

"...It doesn't? What does it have instead?"

"...Not...magic? We have, like, boats and printing presses and midwives and physicians and carts and stuff."

"What-all kinds of thing do you do with magic?"

"I mean, I'm a dragon, we're very magic, I'm using magic right now to be bipedal and non-clawed and stuff. Light our houses? Tell time? Get rid of headaches? Have biologically unlikely children? Not me in the last case, I don't have any kids."

"We use bark tea to get rid of headaches, candles and lamps to light our houses, spark candles, sundials, and waterclocks to tell time, and we don't have any dragons to make bipedal. So I guess we do alright without it."