[2] His paternal grandfather, Moses Cass, was born in Białystok, Vistula Land, Tsarist Russia (now Poland), arriving in Perth in 1906.

[5] On a radio broadcast in June 1969, Cass stated "I have certainly broken the law on numerous occasions by sending patients to other doctors for the purpose of having abortions induced."

He stated that he had performed abortions "every weekend" at Royal North Shore Hospital while undergoing his residency and that he was "sure that most doctors are in the same position".

[7] He stood in safe Liberal seats at the 1961 and 1963 elections, running against Prime Minister Robert Menzies in Kooyong and John Jess in La Trobe.

[11] In October 1973, Cass seconded former prime minister John Gorton's motion for the decriminalisation of homosexuality, which was successful although it had no legal effect.

[16] Following the dismissal of the government and Labor's defeat at the 1975 election, Cass was named opposition spokesman for health in Whitlam's shadow cabinet.

[17] When Bill Hayden replaced Whitlam as opposition leader in December 1977, Cass was given the portfolio of immigration and ethnic affairs.

[25] His second child Deborah Cass was an academic lawyer at the London School of Economics whose writings and teaching were widely admired in Australia and overseas.

[28][29][30][31] Cass is incorrectly believed by some to be the originator of the saying, "We do not inherit the earth from our ancestors; we borrow it from our children" (although a similar paraphrase was used earlier by the environmental activist Wendell Berry).

Anyone who fails to recognise the basic validity of the proposition put in different ways by increasing numbers of writers, from Malthus to The Club of Rome, is either ignorant, a fool, or evil.Cass's version was a longer explanation than the original, traditional proverb.

Cass has been cited as the first person to use the term "queue jumping" in reference to asylum seekers, in a 1978 opinion column in The Australian.