I have managed to find from Scotlands People the birth certificate for my gg Uncles and Aunts from the marriage of Andrew Ballantyne and Maria Millar (married 12th Oct 1865). My gg father was Andrew their first born 27th June 1866 but I can't find his birth certificate. I have them for this 6 siblings, William, John, James, Ann, Margaret and Walter all born between 1868 and 1880.
It seems strange that his is the only one I can't find him, they where all born in Galashiels.