My great grandfather fought in World War I. My grandfather (mother's side) was in the Pacific (Navy) in WW II. My great-uncle (father's side) was with the 101st Airborne for the European Campaign in World War II (he made it through their entire campaign from D-Day on). My other great-uncle (brothers) on my dad's side was also in the 101st, but post-WW II (he was a lot younger). My dad's dad was rated 4F and was denied enlistment for WWII. I think it haunted him his whole life.
My father was in the USAF from 1963-1967; he had a kid in 1965 and was stationed in Europe. My uncle (dad's brother) was in the Army from 1966-1971 (enlisted, volunteered). Of my dad's other 5 brothers, I have a USAF vet, two Navy vets, and am Army vet. I have one uncle that didn't serve. On my mom's side, my two uncles were in the Marines.
My younger brother served with the 7th ID (Army), my older brother was a mobile air traffic controller in the USAF from 1984-88, and I myself was a Terminal Attack Controller (I called in airstrikes) in the USAF from 94-98. I was attached to the 4th ID and 3rd ACR out of Ft .Carson, CO.
In my family, military service is an expectation. I don't think there was much of a question about it.