There had to be something before Ken and Mary, right? They must have come from somewhere and it probably wasn’t a Nissan Skyline that gave birth to them…
Ken's parents get married in a Skyline S50
The Nissan Skyline C10 was the third generation Skyline and the first car released after the Nissan and Prince Motor Company merger and the fourth Skyline model became famous for its Ken and Mary commercials. Before merger the Skyline range belonged to the Prince Motor Company and I personally consider the Skyline as a manly car. So the Prince Motor Company must have been the parents of Ken while Nissan must have been the parents of Mary.

Prince featured Ken’s parents their commercial for the second Skyline model (S50):

So now we know that Kens parents loved skiing and were god fearing christians. ;)

Direct link to video: スカイラインのあるところ、ここにも幸せが。