Image imported from derpibooru 
Original Description:
 
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Gen 1- Tender Rose and Cloudy Days got married and had Fluttershy and Zephyr Breeze.  
Pear Butter and Bright Mac got married and had Big Mac, Applebloom, and Applejack.  
Windy Whistles and Bow Hothoof got married and had Rainbow Dash
 
Gen 2- Fluttershy married Big Mac had Spring Daisy.  
(Discord and Fluttershy had a child before big mac but I forgot to add her).  
Applebloom and Diamond Tiara got married.  
Applejack, Soarin, and Rainbow Dash are in a throuple and they had Maple, Moondazer, Acid Cloud, and Thunderclap.
 
Gen 3- Spring Daisy and Maple are direct cousins  
while Moondazer, Acid, and Thunder are cousins by marriage (indirect).