@Background Pony #2E6B  
Because of 2 reasons.  
#1- Pinkie Pie being Pinkie Pie.  
#2- Family for Applejack is serious bucking business.

@Techy Pony  
Just like in real life! (and /b/ <.<)

@OneOverTwo  
If they’re concerns about being related then she’s family with every pony, it’s a matter of how closely.

@Background Pony #2E6B  
4th cousins twice removed, even further apart. The way they stated it in the beginning it actually sounded like one of Pinkies ancestors was a 4th cousin twice removed of one of AJ’s ancestors making it sound like they could be even less related. I thought the premise of the episode was stupid, even if it was an entertaining episode.

@Background Pony #2E6B  
It was a big deal because Pinkie was really excited ’bout the prospect of being family with one of her closest friends.

@Background Pony #2E6B  
Excuse for a fun road/river trip.

This is a bit late don’t you think?

@OneOverTwo  
Hold your horses (no pun intended). They are only fourth cousins. Then what was the Point? What was the big deal? I hardly know my fourth cousins. This should have been a “oh, that’s cool I guess” scenario. Not a “we have to find an apple family genealogist” scenario.

OP, it’s already happened and I think most of us have concluded that it’s stupid to call it invest. That being said, it’s not like half the people on here are bothered by incest anyway.

Fourth cousins = Incest not really being an issue.