In this fanfiction, Beast Boy could turn into a girl because of an encounter with an alien artifact. As a girl, he discovers new aspects of his powers. Maybe he can now communicate with different animals in a more empathetic way. His relationships with the other Titans change too. Starfire might take her on shopping sprees, thinking she needs more 'girly' things.
Well, he could start breathing fire uncontrollably and accidentally set the Titans' tower on fire. Then he'd have to figure out how to put it out while still in dragon form.
One possibility is that the story focuses on how Raven and Beast Boy adjust to being parents. They might face difficulties like protecting their baby from villains who want to use the baby's powers for evil. The baby could also be a key to uniting different factions in their world, so there would be a lot of political intrigue around it as well.
Well, obviously, baby Beast Boy is a main character. The other Titans like Robin, Starfire, Cyborg, and Raven often appear as well. They play important roles in taking care of baby Beast Boy or helping him with his powers.
One interesting plot could be baby Beast Boy's first encounter with other Titans as a baby. Maybe he accidentally turns into different animals and causes chaos in the Titans' tower in a really cute way.
There could be fanfictions where Beast Boy is babysitting or being babysat. For example, a story where he has to take care of a younger teammate's pet or a small child in a comical situation. He might use his shape - shifting abilities to entertain the little one.
There was a boy. Due to a magical spell gone wrong, he turns into a baby girl. His life completely changed. He was now small and delicate. He couldn't do the things he used to do as a boy like climbing trees or running around roughly. Instead, he had to learn to be more ladylike. His parents were also very surprised but had to adjust to this new situation. They bought him girl - appropriate clothes and toys. Slowly, the boy - turned - baby - girl started to adapt to his new identity and the world around him changed its perception of him too.
It could be Trigon. Since Raven has a connection to him, he might see the baby as a way to get revenge on Raven or as a powerful tool for his evil plans. He could try to corrupt the baby's powers for his own use.