Gudjohnsons were the ones that sprung to mind for me. I think Eidur might be the only player to come on as sub for his Dad in an international match?
I wondered about the Charltons (brothers, I know) but Jackie didn't get close.
The Ayew brothers both have over 100 caps for Ghana, but their dad only got into the 70s; would have made 100 easily in the modern game.
Always felt a bit sorry for Kasper; from the age of 17, his middle name has been "not as good as his dad". Worth remembering that Peter didn't move to England until his late 20s and probably made his mistakes before anyone here had heard of him. Not many keepers have been in his class since, but they're not burdened by comparrison.