Last Night's TV: John Barrowman: The Making of Me, BBC1<br />Travellers' Century, BBC4

Three questions arising from the title of John Barrowman: the Making of Me: what made John Barrowman the way he is? Could you put it in a bottle? And having put it in a bottle, could you row it out to sea and sink it? I'm not saying I'd necessarily do that, but after an hour of The Making of Me, I think I'd like to know that the option is available.

The programme opened with Barrowman – Captain Jack from Doctor Who – backstage, preparing for an appearance in his sell-out one-man show, in which he belts out songs from the shows. Barrowman is, not to put too fine a point on it, the kind of man who likes musicals. You know what I mean. Not that there's anything wrong with it. But what made him that way? Can a leaning towards Stephen Sondheim be learnt, or is it determined by your biology?

To find the answer, Barrowman went on a journey of self-discovery, interrupted by scientific and not-so- scientific tests. The first of these was designed to discover how good his gaydar was. Could he tell another gay man just by the way he dressed and walked? Ten men, half gay (I mean five out of the 10, not that they were just gay-ish), were paraded in front of him on a stage, and he wrote down whether he thought they were gay or straight. Interestingly, Barrowman's score was not high, though I'm using the word "interestingly" in a loose sense here. It was interesting in the way pictures of Brad and Angelina's babies are interesting. What it contributed to the nature/nurture problem remained vague.

Barrowman headed back to his homeland, the United States, where scientists – that's another word I'm using in a loose sense – strapped him up to a "penile plethysmograph", a kind of lie detector originally designed to weed out heterosexual men faking homosexuality to dodge the draft. Seated on a chair covered with conspicuously wipeable material, Barrowman was shown a selection of straight and gay porn: to his relief, only the gay stuff worked. An MRI scan confirmed that the relevant bits of his brain lit up only when shown naked men. Back in his home town, he showed off his closet (not a place he's spent much time in), with its astounding collection of Barbies, and a rare and valuable Sonny and Cher doll set – and there was I thinking Waylon Smithers, a secret admirer of Monty Burns and the author of Sold Separately, the Malibu Stacy musical, was a caricature. His childhood best friend, Laura, recalled how she used to play at being a hairdresser, with young John as her trainee, and how much he loved Abba songs, particularly "Chiquitita": "If that's not a red flag!" He met the Alexander twins, Jared, who loves GI Joe and guns, and Adam, who likes My Little Pony and Bratz. All evidence, he reckoned, that sexual preference is determined from birth, though I wasn't quite clear whether we'd actually decided Adam was gay. Here was a fundamental problem with the programme: it assumed that being gay meant not just liking men, but having what one scientist referred to as "gender nonconformist behaviour". Speaking as a sport-hating, classical-music and Cole Porter-loving heterosexual, I felt the terminology needed unpacking a bit.

There were entertaining moments. The researcher who, fitting the plethysmograph, whooped, "He likes that!"; the brain-imaging guys who teased Barrowman that his brain structure had proved he was really straight; the formerly homosexual Ron Woolsey, who abandoned his old ways to be a better Christian, and offered this analogy: "To this day, when someone lights a cigarette, that smell is attractive to me. I don't smoke, though." But does he still need nicotine patches? But for the most part, the programme was an odd mix of the bogus, the misunderstood, and the merely frivolous, and it failed to address a much more intriguing question: how is it that Barrowman, at home in America with his Scottish-born parents, speaks with a strong Scottish accent, but back in England turns all American?

In Travellers' Century, Benedict Allen paid tribute to the writing of Eric Newby, whose Love and War in the Apennines and A Short Walk in the Hindu Kush are two of the great travel books of our day. It was, as programmes about Newby tend to be, elegant and amusing, his gift for local detail and self-deprecation apparently transferring effortlessly to anybody who tries to describe his appeal. The thing that partly spoiled this for me was the way that, like The Making of Me, and so many other programmes these days, it had to be cast as a quest for understanding, Allen following Newby's footsteps in an attempt to find out what drove him. I don't understand where all this need for understanding comes from. What's wrong with Benedict Allen saying, "Eric Newby's terrific, let me tell you his story"? Why the pretence that he has to get inside his skin? That's not what we do with writers. Imagine being inside Graham Greene's skin, or Kingsley Amis's – how revolting it would be. But they both give you a point of view, a style, a voice, and that's plenty. All TV has to do is provide an echo.