We haven't planned anything like this for the game just yet, if it's something that a lot of people are clamouring for then we'll look at adding it in future updates.
It can be a lot of difficulty to implement it well, and because the focus of the game is the narrative it can take away from the immersive story telling. For example the MC's blonde hair is important, the MC's penis size might change as he is subject to chastity or magic, rather than customizing it yourself you're choosing the storylines that you like the most for how you want the MC to end up.