First Steps is arguably about how the birth of Franklin Richards affects Earth-828, his family, and the universe in general.

In a 1982 arc by John Byrne, Franklin gets frustrated trying to solve a Rubik’s Cube and uses his powers to age himself into an adult body, though he couldn’t actually gain more emotional maturity. He winds up going back to being a kid, placing restrictions on his own abilities to allow him to have something of a normal childhood.