Masters of Sex: The Complete First Season DVD

You can imagine the pitch meeting for Masters Of Sex: "It's like Mad Men – but with boobs!" Whilst it's not an entirely inaccurate description – there's lots of attractive people in fabulous period costumes, smoking, slow-burning plots aplenty and, yes, boobs (not to mention a never-ending parade of other body parts, both male and female) – it's very much its own show. For a start, at no point in Mad Men does anyone brandish a dildo called Ulysses, although Don could probably do one hell of an ad campaign for it.

Then there's the opening credits – all shots of beavers (the animal kind), cucumbers and corks popping – which seem to have been put together by whoever compiled The Naked Gun's shagging montage. They leave you with the distinct impression that Masters Of Sex is going to be a never-ending stream of cracking knob gags.

Alas, it's not. It's a mostly serious look at pioneering 1950s sex researchers William Masters (see what they did there, they got his name into the title) and Virginia Johnson (she didn't but since her name's Johnson, we can still have a snigger at it), their pioneering work studying sexuality, and their constant battle against prudish establishment types.

The pair conducted the first serious studies into human sexuality, and the show details their research – at the time hugely controversial – the effect on their personal lives, their battle against the establishment, and the unqualified Johnson's struggle to be taken seriously. As the two leads, Michael Sheen and Lizzy Caplan are both excellent, and both throw themselves gamely into their parts (which, yes, is standard reviewer-speak for "lots of nudity".)

Most of the show's drama comes from the relationship between the mismatched pair. Masters is a brilliant doctor looking to conduct the first real scientific research into human sexuality. He's also slightly naïve (look, he's played by a Brit!) and has a less than straightforward marriage. Johnson's the more liberated of the two (she gives someone a blowjob in the first episode which is apparently a huge deal as no one else in the 50s knew blowjobs existed) who's hired by Masters as his assistant. What starts as a purely professional relationship quickly gets complicated when Masters dispassionately suggests early on that as part of their research they should have sex with each other.

Their controversial work – which seems to entirely consist of wiring naked people up to assorted monitors, then looking at lots of dials and printouts whilst their subjects have sex – naturally brings them into conflict with those around them. Masters keeps butting heads with his superiors, and is determined to keep his study going at any lengths, relocating it to a brothel and resorting to blackmail to keep things going. Johnson has to deal with the lack of respect she receives from Masters and others for being both unqualified and in possession of a vagina in a time when such things were frowned upon.

Sheen and Caplan aside, the supporting cast are equally impressive. Special credit goes to Beau Bridges, both for his performance and for managing to be one of the few cast members who keeps their clothes on, as Sheen's not-so-happily married and secretly a-little-bit-on-the-gay-side boss. Masters' unbelievably understanding wife (Caitlin Fitzgerald) and hot-for-Johnson (the person, not the...oh never mind) younger colleague (Nick D'Agosto) also deserve credit, as do Heléne Yorke and Teddy Sears as a pair of regular participants in the study, neither of whom seems to own any clothes.

If the premise sounds overly serious, it's not. The show's more than happy to poke fun at sex, and the naivety surrounding it at the time – look out for the devoutly Christian couple who think, as the Bible says, all they need to do in order to get pregnant is literally lie with each other.

Season two of Masters Of Sex has just started in the US, and arrives here next week (although it's been demoted from Channel 4 to More4, presumably as they've realised showing repeats of Come Dine With Me 24/7 isn't going to be a ratings success forever). It's one of the more enjoyable of the recent crop of US shows: smart, funny, cheeky, imaginative, and a curious reminder of how far we've come in recent years. Not to mention how many times, in what positions, who was first, and whether keeping our socks on makes any difference.