I wouldn't be surprised if this idea has been used before, but bear with me.
Again, thinking about my Titania idea and character concept so captivating just grabbed me.
Imagine a world where you are genetically calibrated before you are born to have the optimal genes of both your parents. Any "bad" genes that carry genetic disorders are taken out, and only "neutral" or "beneficial" genes are kept in. Imagine growing up knowing that your genetic coding was the optimized splicing of your parents, your are considered to be one of a few perfect possibilities due to the luxury of modern science.
And then imagine having a gender dysphoria in that world.