It’s long been confirmed that Jon Snow and Daenerys Targaryen are related (she’s his aunt, being the sister of his true dad Rhaegar Targaryen), but just how incestuous would this romance be if they paid up to fan service and boned like dragons?

Luckily for all of us, a Redditor has done the math – and the answer is really, really, extra icky incestuous. Still shipping Jonerys?

Redditor amacaroon writes while an individual would usually share 50 percent of their DNA with parents and full siblings, 24 percent of their DNA with aunts (i.e. Daenerys), uncles, half siblings and grandparents, and 12.5 percent of their DNA with cousins, the Targaryen’s long-running habit of wedding brother and sister make Jon and Dany an unusual case.

“Targaryen family trees are a special kind of special. They look more like ladders than trees. Dany’s father and mother, Aerys and Rhaella, were full siblings. So were her grandparents, Jaehaerys and Shaera. You have to go all the way to her great-grandparents, Aegon V (Egg) and Betha Blackwood to find a couple that wasn’t closely related. Genetically, this makes Dany half Blackwood, a fourth Dayne, and a fourth Targaryen.

“So because of all this incest Rhaegar and Daenerys weren’t just siblings. They were super-siblings. Normal siblings share 50% of their DNA. Rhaegar and Daenerys shared 88%. That’s approaching identical twin level of incest.”

It means that as Rhaegar’s son, Jon shares 44 percent of his DNA with Dany.

“Genetically, they are closer to being full siblings than to being aunt/nephew. For comparison, Cersei and Jaime share 56.3% [of their DNA, while] Jon and the Stark kids share 13.3%.”

[Remember: Jon still shares Stark DNA, through his mum Lyanna Stark, Ned Stark‘s sister.]

Amacaroon points out that yeah, Dany and Jon are still aunt and nephew, but thanks to all this incest, they’re also first cousins once removed AND second cousins once removed.

“If you want to fully understand how crazy Targaryen incest is, Daenerys’s coefficient of inbreeding is 0.375. (The higher this number, the more inbred the person is.)

Alfonso XII of Spain, who basically wins at being like, the most inbred person ever, had a coefficient of only 0.25.”

Amacaroon later corrects themselves, after a commenter pointed out that Charles II and Cleopatra are more inbred than King incest Alfonso XII. But that’s not the point. The point is: Dany and Jon are related as fuck.

Now if Robert’s Rebellion had never happened, Daenerys and her brother Viserys would likely have wed in true Targaryen tradition.

To put that in perspective:

“Their children would have had a coefficient of 0.5. If Craster [the dude north of the wall who married his daughters and sacrificed his sons to the White Walkers] wanted to match that level of incest, he would have to become immortal and have kids with his daughter-wives an infinite number of times.”

When George R.R. Martin said “the dragon must have three heads”, I didn’t realise he mean as the result of centuries of inbreeding.

Luckily for the general ickiness of incest shipping, Jorah Mormont seems like a pretty good contender to get in the way of any potential Jon and Dany romance.

Also: this comment has well and truly fucked me up.

h/t to amacaroon; go here to read their full post + workings.

Image: HBO