In my immediate family (of nine children), only two of us served. My oldest sister (US Air Force 6 years and her husband retired from the AF), and myself (I retired from the Army, after just over 21 years). My son served in the Air force. My uncle (mom's brother) served in the AF for six years. This is what I thought was the extent of our military service... I "thought"...
Having said that... Through my genealogical research of the last seven or so years, I have found that my paternal lineage (who immigrated to America in 1744) have served in every war since the Revolutionary War. In fact, it was the Revolutionary War, and the War of 1812 (including the "Indian Wars"), that drove my Gregg/Gragg lineage to pioneer from Pennsylvania (Cumberland County), through Virginia, to the Carolinas through land grants due to their military service. And as the States split (Virginia/West Virginia... North Carolina/Tennessee etc...) my lineage who all stuck together in their migrations (were split with the separation of the States as our nation grew).
I didn't have much connection with my paternal lineage until my genealogical research. But when I found out that three of my father's brothers served in three different wars... WW II, Korea, and Vietnam, I couldn't have been more proud of my Military connections.
My maternal side, amazingly enough, immigrated to Pennsylvania in the first diaspora of William Penn. And Both my maternal lineage, and my paternal lineage were farmers in Cumberland County Pennsylvania at the same time. After I found this out, I often wondered if they ever met each other and had any interaction during that time. It may be doubtful, as my paternal side were Scots-Irish, and my paternal side was German (Pennsylvania Dutch), and historically, familial clan-groups kept to themselves for the most part. But it's cool to think that it may have happened :)
When I researched my Material lineage, I found that the Military history was nearly as rich. And three of my mother's uncles served during WW 1 and WW II.
Genealogical research has been a great boon for me to not only understand the military histories of my ancestors, but it has also given me a better understanding of America's history, and given me stories to hand down to my children and grandchildren. It only served to enrich our lives.