There has never been a prime ministerial dynasty in Canada.
John A. Macdonald’s son, Hugh John Macdonald, became federal cabinet minister and the eighth premier of Manitoba, but never prime minister of Canada.
[N.B. Daughters don’t count!]
Wilfred Laurier did not have a legitimate son.
Nor did Robert Borden.
Nor did R.B. Bennett.
Nor did William Lyon Mackenzie King.
Nor did Louis St. Laurent.
Nor did John Diefenbaker.
Lester Pearson did have a son, but Geoffrey Pearson became ambassador and never ran for office.
Jean Chrétien’s son, Michel (born 1968), does not appear to have any political ambitions. He was adopted as a Gwichʼin child from an Inuit orphanage.
If Paul Martin senior had become prime minister, as he wanted to be, the Martins would have become the first Canadian prime ministerial dynasty the moment Paul Martin junior became prime minister.
Justin Trudeau may – or may not – make history.