The Weekend's TV: The Perfect Vagina, Sun, Channel 4<br/> Pacific Abyss Sun, BBC1

The dangers of trying to cut it too fine

It's amazing that anyone but gynaecologists and bikini-waxers have studied enough examples to pass judgement on the precise measurements of the perfect vagina. The debate over the dimensions of the perfect pair of breasts still rages, and we all see plenty of those every day. Most of us, I hope, would share the sentiments of the presenter Lisa Rogers's liberal male pals, who couldn't give the proverbial about how their lady friends' lady parts look. "The amount of hair down there is the only thing that registers," one of them told Rogers during The Perfect Vagina, her documentary on the overlooked subject of vaginal surgery. Yet that hasn't stopped countless women going under the knife. The number of NHS requests for the labioplasty procedure has doubled in five years. Rogers hoped to learn "why girls want to cut up their bits".

A pretty 21-year-old called Rosie wanted to have some of her labia removed after being teased by her sister, who regularly makes derogatory comments about her vagina to Rosie's boyfriends. Rogers seemed to be having the same thoughts as any sane person: it's a new sister Rosie needs, not a new vagina. But Rosie was determined, so we watched in graphic close-up as a cosmetic surgeon performed the grisly operation, with the poor girl, under local anaesthetic, crying on the gurney. Rosie is by no means the youngest patient to have undergone such a procedure. One doctor that Rogers spoke to regularly operates on 16-year-old girls.

There were touches of typical Channel 4 prurience to the programme, not least in its title. Rogers insisted that if she was going to tackle the issue, she had to study her own nether regions, but her willingness to hike up her skirt for her interviewees – waxers, surgeons, a sculptor who specialises in vaginas, and a holistic psychosexual therapist who encourages women to talk to their genitals – didn't contribute much to her investigation. Nonetheless, this was a shocking look at a surprisingly widespread trend. At one point, Rogers encountered a Muslim girl who wanted to have her hymen restored before her wedding night for fear her parents would discover she that wasn't a virgin and kill her. For about 10 troubling minutes, it threatened to become another documentary altogether.

Rogers's admirable intention was to put off any women considering unnecessary vaginal surgery, and I can only imagine she succeeded. But it was also instructive for those men who stumbled across it after reading the title in their TV listings mag. Women may say they're having the op for themselves, but, like Rogers, I suspect it's for the benefit of their menfolk. The simple lesson for chaps: don't be as daft as the decorator painting Rogers's bedroom, who helpfully demonstrated the sort of attitude that could send a sensitive woman home in floods of tears. "It's like the presentation of a meal," he explained, in a charming simile. "You've got to have something that looks nice before you taste it."

There was one particular pleasure to be had as a man watching this documentary (and no, lads, it wasn't a glimpse of some imaginary perfect vagina). Rogers went for a Brazilian at the start of the film, and her technician – who is familiar with the subject – told her that she thought all this self-consciousness about vaginas started after Sex and the City's fabled "bikini-wax" episode. At last! Something specific that we sad, inadequate males can blame that show for.

Someone at the BBC has obviously decided that the best bit of Planet Earth was the 10 minutes at the end of each episode when they showed us how they'd managed to capture all that wonderful footage. How else to explain the existence of last week's Lost Land of the Jaguar, and now Pacific Abyss, two natural-history miniseries that told us more about the film-makers than about the creatures they came to film?

In the minute-long "coming-up" intro that seems to kick off every documentary on television nowadays, we enjoyed the sight of Kate Humble enthusing: "This is why we're here: FISH!" "Here" was Micronesia, an ocean state in the Pacific whose depths are largely unexplored. Humble and a team of scientists were there to survey the seabed and its inhabitants. Yet by the end of the hour, the fabled "fish" were still few and far between. The team were terribly excited by the discovery of three unfamiliar, palm-sized examples, but how were we amateurs to know they were new species? I think these things are more thrilling to marine biologists than to your average TV viewer.

We were treated to a bit of vague history (the region was a battleground during the Second World War, hence the Japanese shipwrecks the team explored), a touch of anthropology (islanders building canoes, previously covered in more compelling detail by Bruce Parry), and a lot of sonorous voice-over about how hi-tech the team's scuba gear was and how they were at the very "frontier of science". But I'm afraid all I could see were three slightly fat blokes in wetsuits, waving fish-nets in the gloaming.