"Well, we don't have a formal distinction between doms and subs, so I don't have stats, but my guess would be that it's pretty uncorrelated? Except to the extent that people who especially want power go into politics or whatever instead. I study biology myself, so that's where I'm most likely to be at all helpful." He had several dreams about variously disastrous failures to reinvent vaccines last night, but hopefully he'll be better at it now that he's any amount more lucid.

"...how do you have a society that does not distinguish doms and subs at all?" James says. 

"Well, it's a spectrum, isn't it? Like, some people actively don't want power over anybody, and some people don't care either way, and some people like it, and some people crave it, and every point in between. And we could pick a point on that line and say, okay, here's the category boundary, but we don't really need a category boundary that much. What do you use it for? And is it a bimodal distribution for you?" It occurs to him that he might need to explain what a bimodal distribution is, but if he explains and James already knew he'll sound like a douche, so he doesn't.

James has a strong sense of propriety and would never admit ignorance in front of a sub.

"We don't wish to scandalize you," the older woman says, "but surely not having a category division makes it harder to form, ah, relationships."

"Oh, you try to have every relationship be one of each? Or two of the same? I guess I can see the reasoning either way. . . . Uh, sorry, I guess at least one of those hypotheses is scandalous."

Judging by James's expression Bruce is totally correct!

"Yes," the old woman says. "Only a dominant and a submissive can marry."

"Okay. Sorry for speculating. For a long time my Earth had it so only a man and a woman could marry, because that's the only way to get children."

"Well, that's a silly way to do things," James says. "What if you don't want children?"

"It is a silly way to do things; most places have stopped requiring it. But most people are still only interested in the opposite gender. Also we've invented a few different ways to avoid accidentally having children, but it was a problem for a lot of our history."

"Genders have opposites in your world?" James asks.

"Uh, it's sort of a shorthand--most people are either men or women and most men are only interested in women and vice versa. I guess calling them opposites is kind of incorrect."

"Your world is very strange and primitive," James says. "I am glad the gods brought you here so you could learn the right way to be."

"I don't think think anything I learn here is going to cause my society to divide up into doms and subs, even if I managed to bring the information home and people believed me about it and decided it was a good way to do things. It's just too much of a spectrum; lots of people wouldn't be able to decide which to call themselves."

"Well," James says, "you can just see which ones can't have children together."

"Uh? Pretty much any man and any woman can have children if they try. Unless one of them has some kind of health problem that means they can't with anybody."

...This is kind of above James's paygrade here.

"...Iiiii think he should talk to Elizabeth Maturin," the older woman comments.

"If your version of humanity has four biological sexes, that's really cool and I'd love to talk to someone about it."

"No, there are only two sexes," James says. "Male and female. There are three roles."

"And every combination of those can happen and both are relevant to being able to reproduce?"

"Yes. --Although it's not proper to discuss sexuality in more detail than this. You're an adult, not a child."

"Perhaps you could round me off to "space alien" if that makes you more comfortable? --Or we could go back to discussing technological exchange, sorry, my curiosity got ahead of my manners."

"What's a space alien?"

"Non-human people from another planet. My universe's humans haven't met anyone from other planets either as far as I know, it's just a concept."

"Like... cyclopses?" James asks.

"Uh, the only cyclopses I know about are fictional people from Earth as opposed to fictional people from outer space, but close enough."