Brought up in a strict Hasidic community in New York, Deborah Feldman could only dream of lipstick and jeans, cigarettes and playing the piano. So what happened when, in her twenties, she renounced her religion?

I grew up in the black-and-white section of Brooklyn, New York. The men in my family wore black hats, black coats and white shirts, they studied black-and-white books and said bright colours were the work of the devil.

I read books, too, but they were in English, not Hebrew, and they came from the forbidden public library, and in their black-and-white pages I was introduced to a foreign, exciting world. The spicy redhead in Anne of Green Gables charmed me; the genders in Little Women kept getting mixed up, but I fell in love with the androgynous Jo regardless; and although Dickensian English did not read easy, I muddled through its glorious convolutions nonetheless.

Because I read books in English I knew I was a bad girl. In a black-and-white world you can either be bad or good. A Jew or not a Jew. There is no in-between. Maybe I didn't wear red nail polish like a shiksa gentile, but I was peeking into an evil world, living vicariously in it through fictional characters. Break a rule and you're automatically on God's blacklist. My grandfather used to say English was an impure language and to employ it in any way would mean employing Satan himself as commander of my heart. There was no doubt that my heart was already thoroughly blackened by the time I was 10 years old.

I doubt it came as a surprise to anyone that I left the Hasidic community. Like my zeidy predicted, I became seduced by the devil. It started with the small things: clear nail polish, subtle eyeliner, a ride on the subway. But then I wanted to see the world, wear jeans, drive a car, learn how to play the piano – all of which were impossible dreams for a woman of my circumstances. Obviously the books worked. Had I never read them, there is no way these desires would have burgeoned within me.

Perhaps it wasn't just the books that made me think sinful thoughts. Perhaps I took example from others. Surely there were rebels before me. There were girls who wore lipstick and sashayed down the main avenue in tight skirts. There were boys who took their hats off once they got to the city and ate hamburgers and talked to girls. All I was really doing wrong was reading secular books.

I remember standing at a bus stop in Stamford Hill when I visited London as a teenager, intent on getting to Harrods so I could buy the newest Harry Potter book. A sexy movie poster for Confidence distracted me; an actress in a low-cut minidress, her hands placed haughtily at her hips, gazed out on to the busy intersection. Two Hasidic women pushing baby carriages down Clapton Common pointed at the poster in horror as they passed by, murmuring in shocked tones: "You know that's so and so's daughter, who ran away when she was 12, with nothing but a knapsack and a few pound notes. Well I guess now we know where she went." The other woman clapped her hand over her mouth in shock, her eyes widening.

I looked back at the brunette actress with renewed admiration. Was that a spark of chutzpah I detected in her smirk? Could you imagine, I said to myself, becoming something like that? Not just disappearing into thin air, but re-emerging years later to gaze triumphantly down at those I had left behind? The thought of it thrilled me. If I left, I knew I'd become something big. Not an actress, but maybe I would write books, like JK Rowling. Maybe I'd show up on a poster, too, and the entire town would gossip about me as they walked past.

Stories of rebels used to be uncommon scandals. Now there is an entire generation of young Hasids chafing against rules that are impossible to follow in an increasingly seductive wave of new modernity. In the age of the iPod, can one really still outlaw an innocent book? Some Hasids prefer to gently stretch the rules, others break them openly. Still, the young rebels swarm into mainstream culture like immigrants fresh off the boat, using broken English to purchase movie tickets and porn rags, rolling up the sleeves of their white shirts to reveal skin pale from lack of exposure. Side-curls tucked neatly behind their ears, they squint in the bright sunlight as if having crawled out of a cave.

I like to think that I am a little different from the others, who sneak out so they can partake in all that is sleazy and salacious. Strip clubs aren't my scene and I don't really like the idea of altering my reality with drugs. I prefer poetry slams and karaoke. Even my English is better, made fluent from years of reading, although perhaps at times slightly accented. (My Brooklyn consonants emerge when I speak passionately.) In jeans and a T-shirt, though, I look like everyone else. And instead of a bogus degree in Talmudical study, I have an actual education.

After I left Williamsburg in 2006, I enrolled in Sarah Lawrence College, a liberal arts college located on a pastoral campus in Bronxville NY. I put my past behind me and made friends with girls who had blonde hair and blue eyes, girls who grew up riding horses and going to prom. For a long time I toyed with the idea of dyeing my hair blonde. I always thought that if I left I'd go straight from being a Hasid to being a gentile, instead I found that I went simply from being a Hasid, to being an ex-Hasid, blonde hair or no.

I was consumed by an obsession with everything I had previously known to be sinful. There was a distinct sensation of relish in everything I did: the first time I danced publicly was exhilarating, the first time I drank beer I got drunk from half a Guinness, and the first time I flirted with a boy I came on too strong.

As a young girl I had yearned to be able to do everything the men were allowed to do. I couldn't smoke cigarettes because that would attract male attention, so I watched while the men puffed prodigiously into the night air and desired nothing more than to be male for a day. Was there a bigger thrill than being behind the wheel of one's own life? Sure, smoking was bad for me. Still, I now did it – and still do – because it reminded me that I had the power to make my own decisions. I wasn't very good at it, but I cherished the freedom to inhale anyway.

Cursing was another indulgence (it may be a sign of poor breeding in secular circles, but I still feel a little thrill every time I utter a swear word). I got roped into trying pork for the first time when I saw a curl of prosciutto resting on a fig and walnut tart. It looked like any other cold cut of meat, so I put it in my mouth. It was only after I swallowed that my friend crowed, "You just ate pig!" Surprisingly, no lightning struck. Pork isn't that big a deal once you get used to it; it's hard to understand why it evokes such repulsion in the Hasidic community.

In the beginning, the small things were enough to keep me happy. I was caught up in the newness of it all; there was a distinct pleasure in knowing how many "first times" lay ahead of me, and an excitement involved in surpassing the milestones. What most teenagers accomplish in a decade I managed to rush through in a year.

After a while though, when I felt satisfied that I had tried enough of what had been forbidden to me, I started to think about the more important things. I have made a point of voting in every election, just for the thrill of knowing I do have a valid opinion. As a woman in the Hasidic community, my singular contribution to society had rested on my ability to marry and have children. My role was special and holy, but it was certainly the only role I could play. Housewife. Mother. For everything else I could depend on my husband. When my professors and classmates at college instantly treated me like an equal, and regarded my opinions as worth consideration, I basked in their recognition like it was the sunshine after a long rain. I read newspapers and talked about politics, slightly surprised each time I was taken seriously. I asked questions without fear of repercussions; I made decisions without wondering if I was going to be criticised.

But while taking delight in my freedom, I also wrestled with sensations of guilt and rootlessness. I felt torn between wanting to be a part of the outside world and convincing myself that it was an impossible goal. This constant state of self-consciousness became an integral part of who I am and how I see the world. When that goes away, perhaps then I will be an official gentile.

I did everything it took to blend in. I drank imported beer. I shredded my jeans. I listened to offensive feminist rap and watched independent films. What made me different from the rest of the students was that I was four years older than everyone else, and when class was finished I went to pick up my son from daycare instead of heading to the pub.

When I was 17 my grandfather arranged my marriage to a young Talmud scholar with golden side-curls and the beginnings of a beard. That's how I came to be a single mother at such a young age. I'd like to explain that to everyone I meet who thinks I'm my son's nanny or, worse, a knocked-up unwed mother. But the story of a teenage girl who forgot to use protection is simpler than the truth, and I allow people their assumptions.

Had my son stayed in the Hasidic community he would have been attending Hebrew school every day from nine to five, and he would very likely have grown up into one of those young men thrown into the real world without even a high school diploma to help them succeed. Such deprivation in this age of opportunity is unthinkable to me. My son might grow up to be an astronaut or a vet. It's his choice. If he'd like to be a Talmud scholar, that's fine, too. But he'll have the opportunity to go to college if he likes, and we read books about hungry caterpillars without feeling a shred of guilt.

I drove away from my marriage, and my religion, for good on the one eve of my 23rd birthday, with nothing but my son and some garbage bags filled with clothes. I changed my phone number and address and didn't tell anyone where I was. To the people whose blood is the same as mine I am very likely lost for ever.

God didn't seem to mind that I now uncovered my hair, drove a car or studied philosophy, but the Hasids sure did. I'd broken the rules and, like the actress on the poster, had proceeded to flaunt it by writing about it in a memoir. Those with the gall to break out of the community are expected to slink away in silence, to disappear into the netherworld of mainstream society. Especially if the rebel is a woman. It is easier for men to find the means and independence to slip through the cracks in Hasidic society. Women are quickly tied down, made financially and emotionally dependent upon men and are rarely faced with opportunities to explore the outside world.

By and large, being ostracised does not pain me as much as being different. I pride myself on being unrecognisable; I like it when people try to guess what ethnicity I am and run the gamut from Lebanese to Native American. If you can't quite put your finger on where I come from, then I've done a good job. Truth is, no matter how great the jeans fit, or how sleek the cigarette looks between my fingers, I will never be able to erase the part of me that is Hasidic.

I have learned to be proud of that, but it took me a long time to get here. I have set down new roots, and I have discovered that my friends have become my family, supporting me in whatever I decide to do, and accepting me for who I am. And that, I have come to realise, is what family is all about.

Deborah Feldman was born and raised in the Hasidic community of Williamsburg in Brooklyn, New York. Her memoir is being published by Simon & Schuster in 2011.

For more information, go to deborahfeldman.com