Hi Jack,
I have a McMillan family from Govan, and the youngest child, Mary McMillan was born in Duntocher abt. 1876.
Her siblings (all born in Govan 1855 - 1868) were Isabella, John, Dugald, Agnes, Donald, and David. Other than Isabella (my direct descendent) I know very little about them, other than the fact that Mary went on to marry a Gray and possibly returned to Govan.
I've been told that there was another sibling, Hugh, based on some family stories - however I can't find any records of him! He should be the youngest sibling, but he doesn't seem to exist.