Is It Possible That Luna & Celestia Aren't Sisters?

[Denim&Venöm 18,264]

Is it possible that the princesses of the sun & moon aren't biologically related as sisters? That their relationship might be, at best as step sisters or sisters in laws? Or more likely, that they call each other sisters because of their shared duties and status? Celestia calls Cadence her Niece, but the book series confirmed that she was just a pegasus who achieved ascendance, and then taken in by Celestia. 

 

So is it possible that maybe Celestia took in Luna as her sister or vice versa? Or can it be a whole "like a sister" or "sister in arms" type of deal?

[Obstinance 21]

Yes, it's possible. It's also possible that Twilight fell out of the carriage on the way out from Canterlot, bumped her had, and everything afterwards was a coma, but it's not something likely enough that I'll lose sleep over the chance it's canon.

 

But if you refer to the fact that "Sister" can be an honorary title, it's certainly possible that's the case, especially since we don't know who the parents of either of them are (Or accurately, if they even have parents).

Edited March 15, 2015 by Obstinance

[Torn 17]

Or maybe my ship is true!! That would make all that fan fiction weird though...

[Steve Piranha 29,411]

Oh my, that's a very interesting question. I think we can rule out the In-laws part, as Luna and Celestia never married so far (confirmed by the staff), or the simbolic siblinghood touched by tribal cultures mostly (these shows rarely shows them, and I don't expect FiM doing it). Otherwise, step-sisters, adopted, being raised as sisters while they are actually cousins or not related at all, sounds plausible as far as we know about the two princesses

[RarityFan01 2,444]

It could be a case similar to Rainbow Dash and Scootaloo for all we know. We don't about their family history. (Unless it was explained in a book or comic that I haven't read.)

[Castle Bleck 19,296]

The Journal Of The Two Sisters said they're indeed sisters.

[Steve Piranha 29,411]

The Journal Of The Two Sisters said they're indeed sisters.

They don't seem to be raised by their parents it seems, and why they were chosen to be made as their rulers? There wasn't any alder alicorns around? I wondered that because it's evident Celestia and Luna were quite young back then

[ArcheoPony 76]

They don't seem to be raised by their parents it seems, and why they were chosen to be made as their rulers? There wasn't any alder alicorns around? I wondered that because it's evident Celestia and Luna were quite young back then

The book said they where taught by other alicorns at some point. Their parents may have been among those alicorns. If I recall, Lauren has always intended for them to be blood siblings, and AKR wrote that book with a lot of Lauren's intentions in mind it seems.

[Dulset Tarn 441]

Luna's real sister died almost a thousand years ago, but her line (and the royal secrets) were preserved over time. That would make this Celestia Luna's great great great (...) niece.

[Pastel 7,630]

In the introduction of the first episode, it is said they're 2 sisters...

I'd trust the book:

Edited March 15, 2015 by Blobulle

[Mesme Rize 15,683]

Well, the series introduced them as sisters and the series still says that they're sisters, so why shouldn't they be sisters?

 

The theory helds no ground whatsoever and is just fanon.

Edited March 15, 2015 by Hypnosparkle

[Sugar Pea 2,682]

I believe that Luna and Celestia are no doubt biological sisters, or there would've been some clue evidence that Luna would have got in the alicorn club because she earned it. I say Luna because of the fact she is the youngest or the two sisters. But who's to say that if it was true that they weren't sisters, would that mean Celestia gained ascendance from the previous princess? Regarding ascendance with both Twilight and Cadence, I want to believe alicorns are made by magic...but if you want to get technical, it could be possible to produce an alicorn through genetics. I'm confused now. ._.
Lol
 

[1Bit 1,531]

while I have no reason to agree with this theory, I understand the idea behind it.   Could make for some interesting storytelling 

[Vinyl Scratch (Filly)™ 936]

Yeah, it's possible. But even if they weren't, they might as well be with how long they have been together for (not including banishment time) I read a story once, can't for the life of me remember what it was about; but in it Celestia was a unicorn who had ascended, and was used as a figure head by the unicorns, around the time when Princess Platinum was alive. Luna was originally a pegasus, who once she had ascended was kicked out of the pegasi kingdom, and sent to the unicorns, where she met Celestia.

 

At least that's how I remember how it went, it was pretty good and believable. I also want to point out that Lauren Faust had once mentioned that Luna had her own castle, which leads me to believe there's a real possibility that they aren't related. Although, that's old news, and since she isn't working on the show anymore, it's been made obsolete.

[Prince Firemane 309]

An interesting theory and very certainly possible. However, I believe them to be biological sisters simply due to the fact that the two of them have waving manes and tails while Cadance and Twilight don't.

[Batbrony 16,040]

To be fair to the OP, we technically have never gotten canon confirmation that the two are biological sisters; that said, nothing we've seen in their behavior towards each other has suggested that they're anything other than biological sisters, so I'm going to say that Celestia and Luna are more than likely biological sisters as I've always thought they were.  Still, it's a curious notion to be sure; way to think outside the box Denim&Venom! 

[CandyStrike 603]

An interesting theory and very certainly possible. However, I believe them to be biological sisters simply due to the fact that the two of them have waving manes and tails while Cadance and Twilight don't.

I agree that they are biological sisters, but I don't think the mane proves that.  In Twilight's Kingdom Part 2 when Twilight Sparkle is given the other 3 alicorn's power she temporarily has a flowing starry mane.

[Nature's Spell 526]

The simple answer is normally the most correct so I agree with the consensus that they are biological sisters. That's not the issue. What we need to see is their past and origins shown more directly. We saw them in Princess Twilight Sparkle exactly as they appear now, which is a shame. Making them look visibly younger and inexperienced would have been fun for fans and good for Twilight to see.

Edited March 17, 2015 by Nature's Spell