I only have anecdotal evidence, which of course isn't convincing but finding accurate statistics on this isn't easy.
When my dad was a teenager, he sneaked out of his parents' home then came back early in the morning (at 3am or so). His dad heard something and went downstairs, nearly shooting my dad thinking he was an intruder. He got rid of his gun the next day.
Even if you could find convincing statistics on accidental shootings, it wouldn't include the many close calls like that case.
I wouldn't mind owning a rifle, for target shooting or hunting. But if someone broke into my house, I'd rather have bear spray or pepper spray than a gun when confronting them. I think bear spray would probably be more likely to work (even if I miss, which isn't likely, being near the stream would probably disable the intruder), and I don't have to worry about killing someone (either the intruder or a relative), I don't really want to kill anyone if I don't have to. I've read many stories of people who have killed teenagers breaking into their homes who felt tremendous guilt later on even though they were legally defending their homes.