It was made pretty clear in the novel that both Santino and Tom Hagen are the same age - 35, and that Michael is 10 years younger - 25.

If this is true, then wouldn't Santino having fist fights with Michael - even if Michael started it to prove he was tough - constitute child abuse? After all, if Michael was 7, Santino was 17. Not quite an even match.

Puzo wrote that both had fights growing up quite a bit, but wouldn't that be kinda far-fetched?

Then, in the film version, Puzo and Coppola put their ages just four years apart.