"Hell if I know how I got here, but yep. I mean I sorta do, but the genre of solves-everything that I am isn't 'alien lands with FTL and shares,' it's that I can make arbitrarily-sized pocket dimensions, I've got a couple cities tucked away in the closets here." 

"- ha ha," he says, "well! That's! Not going to help if we have an asteroid strike the planet but will certainly handle a lot of things short of that!"

"I could maybe handle that too, being able to make pocket dimensions isn't the entirety of my power. I admit I haven't tried to solve that particular problem before." 

"How would that work exactly - she didn't tell me what-all you can do, only that you're an alien, or rather that you were at least one of an alien or a few other things -"

"Some other aliens are meddling with my homeworld by way of giving people powers. Mine is that I have complete control over stuff that counts as 'within my domain,' like a house I own or someone who swears fealty to me." 

"...how do the other kinds of aliens... do that?"

"Hell if I know." 

"Oh. Is it magic, magic outright, or...?"

"Either that or technology sufficiently advanced as to be indistinguishable." 

"Well, there is a difference, though, you understand..."

"I do understand, I just can't tell." 

"- sorry, uh, did you want to talk about evolutionary biology? I am not precisely clear on my agenda."

"Oh, it's fine. The people I talked to before were surprised my species wants children less than Amentans do." 

"That's very surprising! Even animals are highly motivated to reproduce. Even the ones that don't rear their children!"

"We do reeeeaaaally like sex. And only invented birth control a couple decades ago." 

"Hm. What about abortion, has that been invented?"

"Yeah, but it's--controversial. Not everyone is convinced that fetuses don't count as babies." 

"...so a lot of people of your species just wind up with children they didn't want but didn't not want badly enough to murder?"

"I mean, we don't want kids as badly as you, that doesn't mean we don't want them at all."

"How many would average people want if they could have as many as they liked with no regulatory, financial, or other barriers?"

"In most developed countries where birth control is readily available and there are meaningful financial disincentives to reproduce we're skirting along at juuuuust under replacement. But, like, even people who decide they only want one kid but end up with triplets will love all of them." 

"Under replacement! That's incredible," he says. "There's no sign of this reversing yet?"

"Well, the thing is that not all countries are developed countries with readily accessible birth control, and the ones that are get immigrants." 

"What I mean is, do any sub-populations that for whatever reason, other than lack of birth control access, have more children, seem to be gaining population ground."

"Ah...no, all the sub-populations that tend to have more children also tend to have very bad adult retention rates, for now."