Lorrie21.
I'm no genealogist (did I spell it correctly ?) so please bear with me. The male line of the Youngers quoted followed their fathers as head of the brewery, although not always the eldest sons - I don't have much info on any "missing" sons.
Mary Bleloch (died 1837) married James Younger (1763-1809) in 1789, his father George (1722-1788) had started the family brewing business circa 1764.
Their son George (1790-1853) married Jane Hunter (1792-1890) in 1816.
Their son James (1818-1868) married Janet McEwan (1823-1912) in 1850. His younger brother Robert (1820-1901) moved to Edinburgh and founded his own brewery there in 1854.
Janet's brother was William McEwan who founded the renowned Fountainbridge brewery in Edinburgh - of McEwan's Export fame.
James and Janet had 5 sons and 1 daughter - I have a photo, circa 1858, of Janet and 4 of the boys (the youngest was then unborn) and the girl. This generation, great grandchildren of Mary Bleloch, brought the Younger family to national prominence.
George (1851-1929) became 1st Viscount Leckie - lots of information via 'Google' search engine, or here
http://www.oxforddnb.com/public/dnb/37082.htmlHis younger brother William became managing director of William McEwan's (his maternal uncle) brewery in Edinburgh in 1886 and guided it into becoming one of the biggest brewing concerns in the UK.
Here is McEwan's background -
http://www.oxforddnb.com/public/dnb/50416.htmlTheir younger brother James settled in St.Andrews and gifted the Younger Hall to the university.
The youngest brother Robert became a very prominent legal figure, later Baron Blanesburgh.
Would you like me to post the photo mentioned above ?