There does not appear to be an online tree for this person directly but there is one for whom I believe are his parents. The tree only shows children born 1903-1916 but I think this is because they aren't able to view certificates of younger family members to confirm.
Parents are William James Whiteside who married Agnes Cunningham 10/4/1903 St. Quivox, Ayr. A daughter Jemima Cunningham Whiteside was born 12/3/1916 Station Row, Rankinston (the latter where James Cunningham Whiteside born in 1923). In 1916 William shown to be an Underground Fireman.
Agnes Cunningham bc.1880 Barrhead, Renfrew was the daughter of John Cunningham and Annie Fagan/Fegan. Family then moved to Ayr.
The online tree is on Ancestry in name of William James Whiteside born 1878 Tarbolton, Ayrshire.
However, until you can finally purchase a copy of James Cunningham Whiteside's birth certificate to confirm the above is my own supposition.
Annette