Masters of Sex, Channel 4

Sexual intercourse was, famously, invented in 1963. Before that, of course, babies were delivered by beak. So Channel 4’s Sex Season marks the golden jubilee for shaggers. Perhaps there should be bunting and pageantry throughout the land. Instead we’ve got the blank-firing Sex Box and, as of last night, Masters of Sex.

The pun in the title is the clumsiest thing about this new Showtime drama exploring the work of William Masters and Virginia Johnson, the scientific pioneers in white coats who in the frozen wastes of Fifties America set about researching sexual response. We first meet the gynaecologist Masters (Michael Sheen) in a cupboard with a stopwatch and a clipboard, watching through a spyhole as a prostitute takes a customer from behind. His discovery that a woman would have the temerity to fake an orgasm leads him to conclude that what another of Sheen's characters would call the undiscovered country of female sexuality might require more formal investigation.

A view through a glass dildo with an end-mounted torch does nothing to persuade his boss

His search for a female assistant quickly leads him to a double-divorced mother of two currently having casual sex with Masters’s junior colleague. The stalk-eyed greenhorn can’t stop bragging about this new secretary's hotness. Johnson (Lizzy Caplan) notes that, being a mere secretary, she’s completely unqualified for scientific research. Masters, the sly old dog, says he trusts his instincts. She soon proves highly capable, recruiting a perky young colleague who is mad keen to have a bit of fun while wired up to machines measuring excitement.

Masters may be master of all he surveys, but the hospital for whom he has made pots of money are not supportive of his interest in what they called smut back then. A view through a glass dildo with an end-mounted torch does nothing to persuade his boss (Beau Bridges, pictured below). And while Masters’s curiosity about female sexuality knows no limits, and his ability to conjure babies for his barren patients is legendary, he’s a dry old stick in bed with his own wife Libby (Caitlin Fitzgerald), whom he can’t impregnate, and who knows nothing about his research. Expect Mrs Masters’s face to get even longer.

A 12-parter about sex research is going to need a bit more than two pioneers watching people humping through a glass screen, and you can see where Masters of Sex is going, both privately and publicly: the frigid Masters is no master of sex and the sassy Johnson is quite the mistress, while their interest in sex is going to rock the phallocracy to its very foundations. The period detail – cars, cigarettes and permanent waves - is all impeccably Mad Men, just with fewer clothes on. (This pilot was directed by our very own John Madden.)

But if it manages to keep up interest, it will be in no small part to the two leads. Sheen is gloriously poker-faced and slow-pulsed, while Caplan beautifully embodies a confident modern woman in an era which wasn’t quite ready for her like. The best word she can offer to describe an orgasm is "fantastic". “It's like trying to describe salt to someone who has never tasted salt.” He cracks his first smile, and looks 20 years younger. If he got the double entendre, he wasn’t saying.

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Overleaf: watch the Showtime trailer to Masters of Sex