I just thought of this, which is why I looked up Sunburst groups and joined one. I've seen multiple stories going around where Sunset and Sunburst are related. I've seen ones where their clones, where they are older sister and younger brother...

Honestly, looking at Subursts parents, what if their either cousins(Because honestly, I can't see this

making this

I mean, its likely, but ehh. Anyways, the likelihood of siblings Sunburst and Sunset brings me to my second theory.

Could they be twins? We honestly haven't seen much of twins, only the Cake Twins. And from what we see, they are very powerful and attuned to each other. SO perhaps they got their cutiemark at the same time, resulting in their parents sending them to Canterlot. I know its unlikely, and please, no one hate on me for this suggestion.

I think I prefer the cousin explanation, honestly.

5264026 Honestly, they look like they could be siblings. If they're different, it's because Sunset just didn't inherit the socks/stripes like Sunburst did. But everything else would fit pretty well. Twilight Sparkle and Shining Armor look nothing like each other, but they're still siblings.

5266568

Good point, Pinkie looks nothing like her siblings or her parents. Thanks. ^^

5264033

Oki doke! Go for whatever head canon you want, wouldn't be fair of me ti judge.

5264026 B-But...my headcannon!

5267136

Hey! Its fine. Go for whatever head canon you want, I was suggesting my own. I'm never gonna be so rude as to stomp out others ideas and replace them with my own. GO on, be creative! Write a story, draw some art, make it about your head canon! Its important. I swear. ;)

5267472 Haha alright. I would never discourage anyone from their headcannons either