My father wore boxer shorts - the classic yoke front boxer shorts that you see in old WW2 movies.
I wore the standard tighty whities that most boys wore back in the 60s until one morning, in 7th grade I think, I opened my underwear drawer and all of my white briefs had been replaced with white boxer shorts. I had not asked for them and I guess my mother and father thought that my brother and I should be wearing boxer shorts now. Although it was uncomfortable changing for PE, being the only boy in boxer shorts, I did like letting my dad see that I was wearing the same kind of underwear that he did.
About 10 years ago I went back to wearing tighty whities (that's me in the avatar) but I still mix it up with boxer shorts.
This is what they look like: