Son and heir of Lucius Cary, the 15th Viscount of Falkland (a Scottish title created in 1620) by his first wife, Caroline Anne Butler (md 1962-1990), and heir
apparent to this title. Note the "of", which is rare in titles of this
rank. There are only four Scottish viscountcies - Falkland (cr. 1620 and the most senior), Stormont (cr. 1621), Arbuthnott (cr. 1641) and Oxfuird (cr. 1651).
Alexander's father is thus the Premier Viscount of Scotland.