I'm having lunch outside with a handful of close friends. Wearing a short-sleeved top, I stretch my arms behind my head, then wait for the reaction. "Gosh, full armpit hair. I haven't seen that in a while," says the 50-something husband of a friend.
"Lost your razor, did you?" asks my friend Rachel, as her teenage son swallows, looking disgusted by what is unquestionably his first sight of proper underarm hair: his mother, I know, has an underarm and leg wax and a Brazilian every six weeks, not leaving much change from $200. "Still, where Madonna goes, we all must follow, I suppose," she murmurs, referring to a recent Instagram shot of the high priestess of pop, complete with long underarm hair.
The question of body hair – and what, if anything, a woman is supposed to do with it - sits neck and neck with diet and body weight as a pressing question on the feminist agenda. Ever since the term Brazilian was coined by the J Sisters salon in Manhattan in 1994 for the waxing of all but a small strip of pubic hair, the trend for shaving, waxing or lasering armpit, leg and pubic hair has seemed unstoppable. Facial-hair removal – the faintest down from brows and upper lips – is pretty standard for many women, and three female friends have been offered arm-hair removal in salons, although none has yet taken this up.
The pits: is Madonna leading the trend back to underarms au naturel?
"Three years ago I wouldn't have dreamt of booking a Brazilian from work, but it's not surprising any more. Last year, I overheard a junior booking a Hollywood," says Emma, 34, referring to the extreme version of a Brazilian, in which all hair is removed.
These days, a mere gentle trim of the bikini line pre-holiday is unthinkable. The perceived pressure for women to be groomed and beach- or bedroom-ready at all times has never been more intense, or more lucrative. Research firm Mintel forecasts that the British hair-removal market will be worth £628 million ($1.1 billion) this year.
But since the sight of underarm hair, let alone a messy bikini line, is now fairly rare, it's easy to forget that extreme hair removal is relatively recent. French actor Béatrice Dalle, with her long, dark underarm hair, was considered a sex goddess in the 1980s. And despite the yelps at the sight of Julia Roberts's unshaven armpits at the premiere of Notting Hill in 1999, they only seemed to increase her bankability.
Vintage: even in 1999 the sight of Julia Roberts' underarm hair on the red carpet was considered shocking.
"When I started in the beauty industry 25 years ago, the idea you'd take the whole lot off was extremely shocking," says Rachel Cross, who owns a beauty clinic specialising in laser hair removal and electrolysis. "Bikini lines started getting higher with the trend for G-strings around 2000, but we've seen a big increase in Brazilians and Hollywoods driven by both 20-something and post-menopausal ladies, who either want to try something new in their marriage, or might have started dating again. Contrary to popular belief, this isn't a trend confined to younger customers."
But a run of high-profile women are adopting a public stance against hair removal. In a chapter entitled "In Praise of Pubes" in her tome The Body Book, Cameron Diaz praised the "lovely curtain of pubic hair" surrounding "that glorious, delicate flower of yours". Diaz isn't alone: last year, Gwyneth Paltrow revealed that a sheer Antonio Berardi dress had left her stylists "scrambling for a razor" because "I rock a 1970s vibe".
In New York, stray pubic hairs sprouted on American Apparel mannequins, while Lady Gaga appeared on the cover of Candy magazine with an untrimmed bush. Perhaps most significant was the moment the actor Gaby Hoffmann appeared in Girls with natural pubic hair, suggesting the idea is filtering down to a younger generation.
But none of my friends will admit to leaving their pubic hair completely unchecked. One of my early memories is of my mother making me run my hand over her stubbly legs as a warning about the perils of stepping on to the treadmill of hair removal, but I did it anyway.
I will never forget the extraordinary, humiliating pain of my first Brazilian in New York in 1999. I am a devotee of the humble razor: I think nothing of fast, pain-free hair removal in the bath every few days. I admit I feel pressure to remove a certain amount. It feels neater.
I was relieved, however, that when I undertook to grow out my underarm hair for this article, my husband seemed unfazed. "Are you going for a full 1970s bush as well?" he asked gamely, and when I asked whether he finds pubic and body hair unsexy or unattractive, he sighed. "When you're in love with someone, it's irrelevant."
Growing out my underarm hair felt strangely novel. My children eyed it slightly suspiciously, since it wasn't something they'd seen on me before, but in the years of shaving off the faintest stubble, I'd forgotten how soft armpit hair is. There's almost something cosy about it: it reminded me of sitting on the laps of mums with full armpit hair as a child in the late 1970s. I don't, however, think I'll keep it. Not because it looks wrong, exactly, but because it makes me feel slightly unkempt. Equally, I doubt Diaz and Paltrow, both of whom have fine, blonde hair, would be quite so laissez-faire if they were blessed with a pelt of thick, dark fuzz.
Although women outperform men all over the place, we still feel light years away from shaking off a generalised squeamishness at the functions of the sweating, bleeding female body. Body hair is one of the most visible manifestations of this.
"It seems so odd that at a time when women are more powerful than ever, there's a simultaneous impulse towards diminution, which is what hair removal represents, since it's returning an adult female body to an aesthetic akin to that of a prepubescent child," says the feminist writer and psychoanalyst Susie Orbach. "We remain very scared of the smells, blood and secretions of the human body, especially the female form, and are more comfortable erasing the reminder of these functions all together. All female bodies, whatever their age, weight or appearance, are beautiful, but we'd rather punish ourselves than acknowledge this."
It was to challenge the idea that body hair is ugly that the lingerie firm Soft Paris recently shot a model with thick underarm hair, a decision that "traumatised" the model herself, according to the owner of the company, Luca Armenia. He wanted to "encourage a more open debate about the pressure of oppression and conformity which comes with hair removal. It should be a matter of choice, but that choice has been removed and we've normalised something obsessive. Hair isn't ugly, but we've taught ourselves it is."
The majority of men I spoke to for this article claimed that body hair wasn't a problem. A 22-year-old male friend told me, "Pretty much all girls my age take a lot of hair off, but I recently had a fling with a German girl who was hairy all over. It was slightly shocking to start with, but I admired her, too." (Although, as beautician Rachel Cross points out, "We're seeing a rise in male clients, particularly men in their 20s and 30s.")
Most of my friends claimed they remove their body hair because it "feels cleaner", despite the fact that body hair performs the biological function of temperature regulation, and that there's no evidence supporting the idea that removing hair is more hygienic.
The hair-removal industry is also open to abuse, as anyone who has paid for an expensive and sometimes futile course of electrolysis can testify. Dr Nick Lowe of the British Association of Dermatologists says the health benefits of hair removal are "negligible", although pubic lice are now an endangered species. "But problems arising from typical home and salon removal methods include inflammation, burns, ingrown hairs, infections, cuts and scarring."
So why are we doing it? The easy availability of pornography has undoubtedly played a role, but archaeologists believe Neanderthals were plucking hairs some 100,000 years ago. Roman women used razors and pumice stones to remove facial hair, and singed leg hair with naked flames. Women in Tudor England plucked all hair from their eyebrows, temples and necks, since hairlessness was associated with exoticism. Queen Elizabeth used walnut oil and ammonia to remove her facial hair.
Perhaps it was the association of hairlessness with beauty that caused one of history's most infamous marital annulments. The art critic John Ruskin famously failed to consummate his 1848 marriage to Effie Gray, and his correspondence refers to "certain circumstances" about her body that were "not formed to excite passion". Was it Effie's pubic hair that revolted him?
It was around that time that one of the first depilatory creams, Poudre Subtile, was created. Gillette invented the first female razor, Milady Decolleté, at the start of the 20th century, and in 1915 Harper's Bazaar ran an advertisement featuring a woman with cleared armpits and the slogan "Summer Dress and Modern Dancing combine to make necessary the removal of objectionable hair". A wartime nylon shortage in the '40s meant good business for the first electric women's razor, by Remington, at a time when pin-ups such as Betty Grable enforced the idea that hair-free equalled feminine and beautiful.
"Hair removal is one of the strange things women, and to some degree men, have done in the name of fashion," says the author Lucinda Hawksley, whose book Moustaches, Whiskers and Beards, will be out later this year. "It's just a different look. Like all fashions, I believe there will be a change."
Orbach is equally optimistic. "I've no doubt there will be a backlash against looking like a prepubescent child or a porn star, just as skinny or flared trousers go in and out of fashion. There's something confident and sexy about a woman who has a decent amount of pubic hair, and I think that's an attitude that's starting to filter down to a younger generation."
It's possible the tide has already turned: New York magazine recently reported the arrival of the "full-bush Brazilian" (1970s in front, Brazilian below), a look perhaps more in sync with the organic, yoga-and-sourdough lifestyle to which hipsters aspire than a taut, bare porn star.
I hope Orbach and Hawksley are right. Because, while I feel "neater" removing a certain amount of body hair, I'm struck by my 10-year-old daughter's reaction when she hears me discussing electrolysis: "That sounds horrible and painful. Do all women have to do that?" No, I tell her, we definitely do not.