From yesterday's Parade magazine: "[Hugh] Grant grew up in London, the youngest of two brothers."
Harbrace 4c (1) Use the comparative to denote a greater degree or to refer to two in a comparison.
The metropolitan area is much bigger than it was five years ago.
She's the older of his two children.
(2) Use the superlative to denote the greatest degree or to refer to three or more in a comparison.
The interests of the family are best served by open communication.
Bert is the fastest of the three runners.