Fathers and sons, even grandsons. There's been a lot of that in this summer's Tests - from Nick Compton's 85 in Durban to Kagiso Rabada's 13 wickets at Centurion yesterday.TV has played its part, capturing some fatherly delight in Mpho Rabada and imperturbability in Jimmy Cook and Vuyo Bavuma.When Compton made England's top score at Kingsmead, he outdid his grandfather Denis by 13 runs on the same ground 67 years before.Dashing Denis, the antithesis of his grandson's batting style, made 300 in a day (181 minutes) on the MCC tour of 1947/48, against North-Eastern Transvaal in Benoni.The Comptons are one of only two families where granddads and grandsons have made Test centuries. Nick has two, both against New Zealand; Denis had 17 of them, seven against South Africa, including a double at Lord's.The others are Vic Richardson of Australia and his illustrious Chappell grandsons Ian and Greg. Only four sets of grandfathers-grandsons have played Test cricket. Apart from the aforementioned, to whom the not so illustrious Trevor Chappell needs to be added, there are Jahangir Khan, who played for India before partition, and his grandson Bazid, who played two Tests for Pakistan in 2005, as well as George Headley, the Black Bradman of West Indian cricket, and his grandson Dean, who played for England.When Jonny Bairstow made his maiden Test century at Newlands, his late father was much on his mind. David, who played four Tests for England, spent a few seasons with Griquas and scored a century and 72 in his first match for them in 1976.Not all Test run-makers of the summer are chips off the old block.Vuyo Bavuma would have - like many fathers -wondered where their kids get such talent.Vuyo, who couldn't bat for toffee, watched in vicarious pleasure as son Temba made a hundred with delightful strokes at Newlands.At the Wanderers at least one father would have taken some relief from the pasting his son's team received from the English, especially Stuart Broad.Mpho Rabada was a proud man after his son Kagiso's five wickets in the first innings. An even greater, 13-wicket delight would come a week later.It was in the final Test where we all dived for record books. Stephen Cook's century on debut demanded all number of comparisons.His father Jimmy, watching as calmly from the stands as he did from the crease when he opened the batting for Transvaal in the heyday of the Mean Machine, should have joined his son as the 12th father-and-son pair to have made a century in Test cricket. But Cook snr, as prolific a run-scorer in his day as his son is today, was 39 when he made his Test debut against India. At 62, he is resigned to a Test record of three matches and a golden duck in the first one."If you don't get out the first ball," Jimmy reportedly told his son the night before, "you're already better than me."Of the 11 father-and-son pairs with Test centuries to their names, only one - the Nourses - are South African. By the way, Stuart Broad and his father, Chris, are another.The Nourses were remarkable. Their first-class careers overlapped and in the summer of 1932-1933 they met on opposite sides at Newlands.Dudley (the younger) made 27 and 54 not out for Natal, while his old man smashed an unbeaten 219 for Western Province - at the age of 53...