After having Texas rainbowdash wanted a kid that was 100% her’s and AJ’s,(biologically). I have touched on this subject before here  
Appledash Headcanon by Glorymoon
 
 
Rainbow Dash had gone to Twilight’s castle after a long day working with the wonderbolts. She had worked her tail off that day showing the newbies how it’s done. She was feeling quite sick so decided to check in with twilight. Twilight had quite a bit of suspicions when she had come to her feeling sick. Twilight had asked Rainbow dash to take a test and reluctantly Rainbow Dash agreed. (she didn’t really believe that she could be pregnant. But surprise surprise, It came back positive.
 
 
Faster than lighting Dashie booked it home to tell Aj. AJ was ecstatic. When Dash first said she wanted another kid, AJ was extremely reluctant. Bugt now, to hear these words come out of her mouth made her so overjoyed. Applejack really did miss being able to snuggle with a baby. She could still take it to Texas but best be know he would not be having it.
 
 
Rainbow Dash was very happy until she had a deep realization. She could not partake in being a wonderbolt and even worse she would have to give birth. SHe had heard how much pain it was for AJ and rarity and was in utter shock and you can only imagine how she felt when she found out she was having twins. AJ would often buy her treats to keep her wife from thinking about the pain of childbirth. However it was all worth it for her once she had the twins. Seeing their big eyes and ting hands, It was all worth it.