My pony Oc has a SON!? - Character design

As you might know, my Oc Rusty Gear is Aromantic, but she wanted a son and since she's in charge of the Royal Lab, she started experiments with artificial insemination so there would be no bond between the kid and the donator. [Remember that even though she likes the She/Her pronouns, she has male genitalia, which is why she had to use artificial womb devices]. Her son [name not decided yet], influenced by her mother's passion for science, he'd try it out too. A bit surprised on his slow learning (since they shared DNA and Rusty is a genius), she managed to become his personal teacher when he was having a hard time at school or collage.

I'll be uploading the complete version of this drawing once I decide all of his backstory.

Ass a fun fact, I wanted to practice different bodies, specially muscled ones since I'm planning to draw an adult comic on a traditional way, Japanese style, and since the characters are human, I think a bit of warm up on that would help.