"Without Spencer and Huxley, Darwin's theory of evolution would not have become so widespread. Yet these two men believed that people of all races must come from a single couple (the same parents)."
(Creation vs Evolution - Part 4, 23 July 2006. The sermon note available here)
"Both Spencer and Huxley acknowledge humankind from all races come from a pair of husband and wife."
(“Chrsitianity and World Religions and Cultures” CD -17 till 20 Aug 2007, translator: Yang Tuck Meng, track 5)
There is no documentation that Thomas Henry Huxley (picture above) think that the world-wide distributed people come from a "single couple" (the same parents). Huxley himself wrote in 'Critiques and Addresses' that the issue on the origin of human races is an "open question". He does not identify himself as either as an 'Adamic monogenist' that believes that all races come from a "single couple"( the same parents). In his own words,
"Five-sixths of the public are taught this Adamitic Monogenism, as if it were an established truth, and believe it. I do not; and I am not acquainted with any man of science, or duly instructed person, who does."(Critiques and Addresses; Emphasis added. The online book available here and here)
Rev. Dr. Stephen Tong is wrong here. Huxley does not think that humans come from a single couple. Between the Adamic monogenism and many forms of polygenism , he sees himself more incline to the idea that our current diverse humans distribution around the world comes from a single species through evolution, not same parents.