But he looks a little hurt when he mentions the baby girl and my apparent oversight – or at least he affects to. In fact, the ever-present sardonic twinkle gives him away. For the record, the new arrival is called Grace, mother and daughter are fine, and the girl's 70-year-old grandfather is every bit as doting as you would expect.
Under the circumstances, then, this son of Glasgow could be forgiven for slowing down a little. In fact Sir Kenneth's vigour seems undimmed.
Most recently he's been putting both it and his establishment clout to good use in the campaign to transform a disused hospital building into a new £1.5 million flagship centre for the charity Cancer Support Scotland, the organisation he founded in his front room in 1980 and which he originally called Tak Tent after the Scots phrase for take care. After a successful 40-year career in the field of oncology, and two decades as a significant public figure in Scottish life, this may well be the project he views as his most fitting legacy.
The Glasgow centre officially opens on Friday and is sited in the former Gartnavel Royal Hospital Chapel, an impressive Arts and Crafts-style building designed by Glasgow-born architect John James Burnet in 1904. Its richly-coloured stained glass windows have been retained and a modern extension added.
But inside, while there is still an air of peace, there is less of the sense of piety which flavoured the building's previous incarnation. The workmen are still busy the day I visit, but as Sir Kenneth shows me around, his pride in a job well done is clear to see.
Earlier, over mugs of tea in a nearby office, he talks about his hopes for the new centre and about how the charity was born out of a realisation that cancer patients needed more than just medical treatment. "It's been going in one form or another for 30 years and this is a wonderful new beginning with a new building, new consulting rooms, lovely little garden. It's a place where people can come and hear more about cancer or take part in some therapies that are available or sit in the garden and just relax."
By dint of his intellect, talent and energy – and, perhaps, the fact that he likes talking to people and is a keen listener – Sir Kenneth has spent much of his career in that place where the medical profession intersects the spheres of politics and public appointments.
He is, or has been in his time, Chancellor of Glasgow University; Warden and Vice-warden of Durham University; Chief Medical Officer for Scotland (and later, during the BSE crisis, for England); chairman of the National Trust for Scotland (NTS); and, last but not least, President of the Boys' Brigade.
None of it, he stresses, has been planned. For example he was a middle-ranking surgeon on a fellowship in London when, almost as an afterthought, he applied for the Chair of Clinical Oncology in Glasgow and got it. That was in 1974. A decade later he was approached about applying for the job of Chief Medical Officer for Scotland. He didn't even know there was such a position but he researched it in his local library and decided to throw his hat into the ring. Again, he got the job.
"I could tell you a [similar] story about each of the changes I've made. They've all been completely out of the blue, completely unpredictable," he says. "If I write my autobiography, it'll probably be called I Like A Wee Adventure!".
He's kept a diary regularly since 1993 – "it covers a critical period," he says – and he has archives ("a big room full of boxes") relating to the earlier stages of his career. The "wee adventure" has been well documented by the man living it.
What Sir Kenneth is currently best known for, however, is his role as convenor of the Commission on Scottish Devolution. Dubbed the Calman Commission, it was established in 2007 with the aim of enhancing the terms of the devolution settlement, and was viewed by many commentators as a response to the electoral gains being made by the SNP.
With those gains now manifest in terms of an SNP majority and an independence referendum tabled for 2014, I ask him if he thinks an independent Scotland would prosper. "I don't really want to get into that," he answers. Isn't he worried, though, that he's increasingly going to be asked for his opinion on the subject?
"I'm avoiding being asked about it because I think there's still a lot to think about." But as someone whose thoughts will carry weight, does he think he'll come out publicly either way before the referendum? "I think that will depend," he says finally, "and this is not the time to go into that".
One subject on which he is a little more forthcoming is sundials, which fascinate him. It's more hobby than obsession and began when he encountered a contraption in Stirlingshire which had 40 faces and could tell the time in every European capital. Who needs a smartphone app?
"Time matters quite a lot to me, therefore how time moves has always been interesting," he explains. "For that reason I got interested in sundials and the different types and what they meant. Some of them are absolutely beautiful. There's a lovely one at Greenwich Observatory which has got two dolphins like that" – he makes the appropriate gesture with his hands – "and their tails don't quite meet but that little slit gives the light coming through. It's a lovely piece of art as much as anything, but at the same time very practical and very scientific."
Cartoons are another area of interest, though not the "What's up, doc?" sort. At least not exactly: Sir Kenneth collects satirical drawings and is particularly fond of those which have medicine and medics as their theme. Some are originals – he has a framed series in his hallway at home which still make him laugh as he passes – but most are in slide form and show that as long ago as the Middle Ages, doctors were as much feared as trusted.
He has a couple of hundred, all told, and often bumps into former students who can recall nothing at all about his lectures except the cartoon he showed to illustrate a point. "So they're very visual and often provide a great stimulus for thinking."
Sir Kenneth has three grown-up children, but if a sense of humour is inheritable then his has gone in strength to Susan, one of his two daughters. She was in her early 30s when she swapped a career in law for the rather more parlous profession of comedian.
"She just came in one day and said 'I'm going to be a stand-up," he says. "She was always very good at debating and I wouldn't have been surprised if she'd gone into something more along those lines, politics even. So it didn't surprise us hugely."
Politics and stand-up aren't mutually exclusive, of course, as Susan Calman has shown during her stints on topical radio shows like BBC Radio 4's The News Quiz. As a gay woman she's also been vocal on the subject of homophobia and gay marriage. She "wed" her longtime partner in a civil partnership ceremony earlier this year.
Calman senior is understandably in favour of gay marriage. But can he see any merit at all to the arguments of those who oppose it?
"No. All I know is that my daughter is very, very happily married to another wonderful young lady. They're happy, I'm happy, they show very great love for each," he says. If it's about love, he thinks, then that's all that matters.
Though he professes no strong political views, it's clear medicine's gain is politics' loss. He has hinterland, an asset not evident in many at Holyrood, and opinions that younger ears would do well to engage with. Slipping on both his Boys' Brigade and NTS hats, for instance, he talks about the benefits of structured volunteering programmes for giving young people skills and focus. Come job interview time, it's the kind of thing that makes a difference.
That said, if there's one kernel of wisdom he would impart to an 18-year-old school-leaver it's to go with the flow.
"I've never thought about where I was going in the future," he says. "The important thing is to enjoy what you are doing and if you do that and do it well then opportunities will come – and some of them are going to be quite interesting."
Actually that's not quite it. There is one more piece of advice to be had from him. He tells me about a young woman he met recently who, when he asked her what she wanted to do when she grew up, replied that she wanted to study medicine and become a neurologist. He chuckles a little as the punchline approaches: "I said 'That's not the right answer. The right answer is: I don't want to grow up!'".
Sir Kenneth Calman – physician, knight of the realm and esteemed public figure – is clearly following that same mantra.
sir kenneth calman