Yes, there are likely some fanfics out there that might touch on Gohan and Chi - Chi's relationship in a context that could lead to pregnancy. However, the quality and nature of such fanfics can vary greatly. Some may be well - written stories that explore their family dynamic in a creative way, while others might not be as good.
The plot could start with Chi - Chi realizing she is pregnant. Gohan might be initially shocked but then overjoyed. It could show them preparing for the baby, like Gohan building a nursery with his super strength. And there could be comical moments with other Dragon Ball characters like Piccolo being confused about human pregnancy traditions.
I haven't come across such a fanfiction myself. It goes against the general nature of their relationship in the original series. Chi - Chi loves Gohan deeply and is very protective of him.
If Chi Chi gave Gohan the green light to train, it could lead to Gohan achieving higher power levels and taking on more challenging opponents. Maybe he'd even unlock new skills and transformations.
Gohan is pretty darn strong in the manga. He has moments of extreme power, especially when he unlocks his hidden potential. However, his strength isn't always consistent and depends on various plot developments and training.