Outlander fans have posed a theory concerning Emily’s eldest son, Swiftest of Lizards, who they speculate might in fact not be Young Ian’s biological offspring.

Since the Season 7 finale graced our screens in January, devotees can only anticipate one final season before the series concludes. Amidst the wait, followers are brimming with queries about their some of the characters.

There’s a widespread belief that Young Ian fathered Emily’s son — his fair complexion and features seem to squarely point to this conclusion, reports the Scottish Daily Express.

Yet, a Reddit user going by @negotiate posited an alternative conception after delving once more into Diana Gabaldon’s novels, from which the adored Starz show derives.

Young Ian is a fan favourite (Image: STARZ)

The user questioned on Reddit: “Is Ian the biological father of Swiftest of Lizards?”

They mused further: “I always thought that Ian and Swiftest of Lizards had a spiritual bond only, not a biological one.

“Like Ian was always supposed to have a child with Emily, but when he couldn’t and left the tribe, the ‘spirits’ of the tribe had Emily conceive a child that was spiritually the son of Ian.”

Their insights didn’t end there, as they added: “Now reading through the book again, I see that after Emily’s final miscarriage, Ian and Emily continued trying, but the heart had gone out of her.

“And then her eye started to stray to Sun Elk, and Ian left the tribe. So that would mean that SOL could potentially be the biological son of Ian. Theories?” (sic)

Emily’s son could have a different father (Image: STARZ)

Fans have been weighing in on a theory, with one saying: “You had it right the first time. If you remember Claire’s explanation to Ian about his blood being Rh+ and Emily’s being Rh-, that almost completely rules out their having a child together.

“Severe cases of Rh disease cause stillbirth, which is how every one of Emily’s pregnancies ended. I’m not a doctor, but I’ve read that the effects become worse with every Rh incompatible pregnancy.

“If Ian and Emily experienced the worst effects of Rh disease with the first pregnancies, she is not going to carry a child to term later on with Ian as the father. Swiftest of Lizards represents the child they wanted, but couldn’t naturally have.” (sic)

Young Ian went on to find Rachel (Image: STARZ)

Another chimed in: “Good point but I’m thinking it’s not entirely impossible since Claire implied that that was the issue between her and Jamie. Brianna was born after faith so I do think its possible. Then again, Claire was in the modern world and maybe they were able to treat it.

“I just looked at a genetics chart: if Emily is (–) and Ian is (+-) the child has a 50/50 chance of being (–) or (+-) so I’m guessing its possible for swiftest of lizards to be rh negative.” (sic)

A third fan speculated: “I think he is Ian’s son. Possible *spoiler* I read Diana’s daily lines so this could be from MOHB or Echo (I’m all mixed up) and there was mention of Ian talking to Rachel about swiftest of lizards because he wants to explain everything before marriage.

“It was strongly implied that he is Ian’s son. Didn’t he also tell his father with the implication that he has a son? I mentioned my medical reasoning on someone else’s comment.” (sic)

Another chimed in: “I haven’t reread in a while, but I thought that Swiftest of Lizards was Ian’s biological son each time I read that passage.”

Outlander season 7 is available to buy now on Digital and is streaming on MGM+ via Prime Video now.