Feminist author Erica Jong and her daughter Molly have very different ideas about parenting and sex – one famously bohemian, the other conservative. Kira Cochrane meets them

In Erica Jong's vast apartment, the Manhattan skyline thrusting up to my right, an image of a naked woman sprawling across a wall to my left, we are talking about sex. Specifically, nudity. Erica's daughter, Molly Jong-Fast, is with us and I'm trying to find out what it was like for her to grow up with a writer synonymous with the sexual revolution – that era of feminism, threesomes, consciousness-raising and beautiful, bountiful pubic bushes.

Molly has made some outlandish claims about her mother in the past, and it can be hard to work out what is true, what is satire. Did Erica really saunter around the house completely naked? "She was totally naked all the time," says Molly firmly, "and my grandmother too". She prods her mother for confirmation. "Were you naked all the time?"

"Carmen is just going to prepare a little bit of cheese," says Erica airily, ignoring the question, motioning to a woman working in the kitchen.

"There was a lot of disgusting nakedness," Molly repeats.

"You sleep in the nude," she says accusingly to her mother.

"But lots of people sleep in the nude," I say. "It gets hot."

Her mother goes to fetch fruit.

"Not in America," says Molly. "We have air conditioning. I sleep in six sweaters".

"It's not like I took you to nudist camps for vacation," says Erica, returning with a bowl of ripe figs, "They're good," she says, biting into one. She proffers them graciously.

Some people were concerned about how Molly would cope with being raised by Erica – the woman who published Fear of Flying in 1973, coined the phrase "zipless fuck" to describe a perfectly liberating encounter and became world famous when the novel sold more than 18m copies. When Molly was a child, therapists plagued her with the question: "Are you repressed by your mother's erotic writing?"

Frankly, the idea of Molly being repressed by anything seems absurd. Loud, arch and snappishly funny, she has the mien of a runaway train, words hurtling forth, helter-skelter.

"The men my mother dated were unbelievable. Un-be-lieve-able," says Molly.

"Scumbags!" says Erica, laughing uproariously.

"I mean, this is the problem with my mother," Molly continues. "She is not a good judge of character. She's a wonderful person. She's very trusting – the kind of person who gives her stalker her cell phone number." (Probably not any more. A few years ago, Erica wrote that she had stopped answering fan mail after one man requested her used underwear and another invited her to become "Mistress of Measurements" for his club, The Hung Jury.)

"I don't know how she found Ken," says Molly, referring to her mother's fourth husband, with whom she's been for 22 years, "because each boyfriend was worse than the next."

She starts running through a list of possibly libellous, possibly entirely true stories about the men in question – a glittering roster of fat jailbirds and motorcycling drug dealers.

"She had one boyfriend I loved and I was so disappointed she didn't marry him. But I think he was homosexual. There was another I liked, too, but he was married to someone else. Also, he wasn't successful. The only guy she ever went out with where I was like, 'Damn, he got away,'" she gives a loud, regretful finger snap, "was [financier] Steve Schwarzman."

"A Republican," says Erica.

"But we would be so rich," says Molly. "I'm just saying. It's a little disturbing."

In her memoir Girl [Maladjusted], published in 2006, Molly wrote about her "semi-celebrity childhood" with Erica, who divorced Jonathan Fast, her third husband, when their daughter was four. After that, Erica spent most of the 1980s dating, and this made it possible, wrote Molly, "for me to get married at a very young age and still know what's out there". The main lesson she learned during this period was never to date a man who "has more than one personality or is currently receiving electroshock treatment".

She returns to this subject in the essay "They had sex so I didn't have to", a highlight of the new anthology, Sugar in my Bowl. The book was edited by Erica, who wasn't sure she wanted to preside over a collection of sex essays by women – more typecasting, she thought – until the stories began rolling in, in all their juicy variety.

Editing the collection, Erica noticed a strong generational difference. "The older women were much raunchier," she says. Molly, who never passes up an opportunity to be outrageous, suggests that this is because the only people who like writing about sex are "the ones you would never want to have sex with in a million years, the 70-year-olds".

Her 69-year-old mother balks mildly. "Fay Weldon?" says Erica. "You wouldn't want to have sex with Fay?"

"Well, I love Fay," Molly concedes. "But not in that way."

Molly maps out the gulf between young and old in more detail in her essay, writing that while her mother grew up in a culture where sex was secretive and tightly tied to marriage, she grew up in a sex-obsessed era, with Britney Spears, for instance, constantly on-screen, "pulsating in a bikini, musing on her virginity". They each reacted against their circumstances, and against the mores of the previous generation – as did many of their peers. As Erica writes in her 1994 memoir, Fear of Fifty, "rebelling generations follow quiescent ones, quiescent ones follow rebelling ones and the world goes on as it always has".

So Erica became a sexual rebel among rebels, rolling through relationships with men and women, writing ecstatic, funny books that celebrated sexual pleasure and opportunity and imagination, literary, significant novels, whose pages nonetheless fall open at the dirty parts when you pick them up in charity shops.

Their life was full of privilege, affluence and anxiety. As a single parent, Erica supported two households, in the country and the city, and had to be very driven, she says. "I kept thinking I would never get another book contract and I would be broke, and it was really scary."

A nanny helped to look after Molly, and she was determined to give her daughter space to develop. Now, she fears, women are being shunted back to the home. She recently wrote in the Wall Street Journal about the rise of helicopter parenting, "the smothering surveillance of a child's every experience and problem", an approach, she believes, that imprisons women.

In response to Erica's motherhood essay, Molly wrote that she spends "a ton of time with my children, never travel, barely work and am a helicopter parent like you can't believe". Now 32, she married at 25, and had three children – Max, seven, and three-year-old twins, Darwin and Beatrice. Her husband used to be an academic but, says Molly: "I helped him out of that. I was like, being a college professor is so stupid." He now works in finance. In 2007, it was reported that the family had moved into a $5m apartment.

Molly writes in the anthology: "In the eyes of Erica Jong, I am a prude … a low-rent yuppie, shuttling my children back and forth to the various and sundry activities and involving myself in the Parents' Association. I am the person my grandmother and mother would have watched in silent scorn. I sometimes tell my children that my most important job is taking care of them."

I can't quite imagine Erica looking scornfully at her daughter. Throughout the interview, as Molly speaks, coming across like a contrarian in her cups (while drinking nothing harder than water), Erica gazes at her through pretty, saucerish eyes. She looks astonished at what she has created. Astonished and proud. There is none of the envy or resentment that can characterise mother and daughter relationships; they praise each other's writing, say they couldn't do what the other has done and finish each other's jokes. "You are funny, Molly," says Erica drily, as her daughter whips forth another wisecrack. "You really are."

Erica once wrote, "Women identify with their mothers automatically and powerfully, but they must also overthrow their mothers to become themselves." In Molly's case, the task of establishing her own identity and voice must have been especially tough. There were difficult years. As a teenager she was bulimic – partly a reaction, she has written, to Joan Collins telling her she was too fat to go on the yacht belonging to Valentino, the fashion designer. And she checked herself into rehab, aged 19, to address an addiction to booze and drugs. She has been sober ever since. But she seems to have established herself now and with aplomb.

She has just published her second novel, The Social Climber's Handbook – the story of a woman who becomes a serial killer to aid her husband's career. Molly says it's about seizing power in a world that doesn't value you. "I know a lot of people, a lot of wives, who don't work now. The problem is that so much self-esteem, especially in New York, is tied up with your importance. You just don't have much if your children are the only people who think you're important."

"So you're saying women can only get power by murdering people?" says Erica

"Yes. That's the only way."

"Murder is the new feminism!" the two women say at once, laughing.

Molly glories in the differences between herself and her mother. Where Erica is bohemian, Molly is bourgeois, where Erica is liberal, her daughter has an edge of conservatism. It's difficult to tell how many of Molly's stories are strictly accurate or wildly satirical. I decide to test a few more of them. Is it true that when she was growing up the house was full of pictures of "naked lesbians fooling around"?

"The naked lesbian painting? Yes indeed."

"It was a gift," says Erica, pouting slightly.

"But it doesn't matter if it was a gift. It existed ... There was a lot of naked art. Even in this house there's a lot of naked art." Molly turns gleefully to her mother. "I'm taking her into the bedroom so she can see the erotic carvings. I will do that. Because there is a lot of really dirty art in this house. What about the guy with the pipe? Where's the picture with the pipe?"

"It was sold."

"Oh, that breaks my heart. A man sodomising another man with a pipe has been sold."

Erica has had open relationships in the past and Molly writes that both sets of grandparents had open marriages too. I ask Erica if this is true of her parents. Molly jumps in, "Well, he cheated on her."

"I don't know if that's considered an open marriage!" says Erica.

"It's open on one side," says Molly. Erica says she doesn't have an open marriage any more because they don't work. "People get jealous. There are very few who are capable of it. I know one or two of the old bohemians, now dead, who were able to do that and weren't possessive, but jealousy is very hard to eradicate."

She says she didn't dare give Molly sex advice when she was growing up: "She would have laughed me out of the room." Molly certainly cracks up at the thought of some sex advice her mother gave one man they know, "who had a nice marriage and always felt close to Mum, and came to her for relationship advice". Her eyes widen, teeth glint. "Dun, dun, DARRRRR!" she says. "He told Mum, 'I'm going to have a ménage à trois with this young woman – what do you think?' And Mum said, 'Do it, it's great!'" She holds up a thumb sarcastically.

"I did not!" says Erica.

"And dun, de-dun, dun-DAR – he left! They got divorced and now he's with a young woman. Wa-wa-wa-WAAAAH."

The only time Erica risked giving sex advice to her daughter was when she was asked for some by one of Molly's childhood friends. The two girls were about 11. "She said, 'How should we decide who to lose our virginity to?'" says Erica, "and I replied, 'Make sure he's really nice and won't talk about you to other people.'"

Molly goes off to phone her therapist and Erica says she feels she was much more "suppressed by my mother than Molly was by me". Erica's mother wanted to be a painter but faced serious obstacles. At art school, for instance, she was told she had missed out on the top prize of a travelling fellowship because she was expected to marry, have children and give up art – and this filled her with rage. This frightened Erica away from painting, which she loved, too. "I was very overwhelmed by her because she was a very strong character. Much more overwhelmed than Molly was."

The two women seem impeccably close – the day after our interview they are off to the Hamptons together, on holiday. "I'm very proud of her," says Erica. "She's taken on things I never did. I had one child, she has three. She's brave. And she must feel very loved, even though she says she has low self-esteem, because otherwise how could she satirise me? She knows I'll never take umbrage. I give her permission to be whatever she wants to be."

And wasn't that the promise of the sexual and feminist revolutions? That women (and men) would be liberated to define themselves as they wished. As a prude, helicopter parent and biting social satirist, Molly Jong-Fast is honouring her mother's values in the most unexpected way.

Sugar in My Bowl, edited by Erica Jong, is published by Harper Collins, £12.99. To order a copy for £10.39 with free p&p, go to theguardian.com/bookshop or call 0330 333 6846.