Good observation. Sadly, Mitt and his four sons had no military experience.
Note that most US Presidents have had daughters - weird - GW Sr. had one, W had 2, Nixon 2, LBJ 2, JFK 1, Carter 1, Reagan 2, Clinton 1. Ford 3. Obama 2.
Rule of thumb; If a candidate for POTUS has a son - he had better be in the military - or have served. I think it may be subliminal.
GWH Bush had another daughter who died and 3, or 4 sons. LBJ had an illegitimate son. (Spittin’ image. Died before it could be proved.) JFK had 2 sons, one who died at birth and one who died in his 20s. Carter had several sons. Reagan had 2 sons (one adopted). Ford had only 1 daughter and 3 sons. We’re not sure whether Clinton had any children at all ;)
So, I count 15 sons vs 15 daughters. Seems to me that the sons are holding their own.