Saturday 8am, Manchester Piccadilly station, and the train to the airport is sprinkled with teenage clubbers. Manchester airport itself, all halogen floorspots and burnished metal, is buzzing. There is a special offer on Eccles cakes at terminal two and the concourse is heaving with families on half-term breaks to Orlando and Gran Canaria. Every year 11 million people pass through the airport and this is where a man with a mission to help people understand genetics has set up his stall.

"We've had nine in already," announces Maurice Super when I arrive at The Gene Shop. "Bit quiet for a Saturday." The aim of Dr Super's brainchild is to equip people with some understanding of genetics - from genetic diseases to gene therapy - that will help them make rational choices when and if they are faced with a genetics-related dilemma. A collaboration between the University of Central Lancashire and the Royal Manchester Children's Hospital, the shop is staffed during the week by health workers from the hospital, and by Super on a weekend.

Appropriately, the Gene Shop is between the Body Shop and the prayer room, a point not missed at last spring's launch - "what keeps body and soul together? Your genes!" Its logo - four stick men and women in a row - looks like the sign for a multiple occupancy loo, while the interior is all soft blues, pinks and pale wood. There are user-friendly interactive computers to lure bored teenagers, a family tree of haemophilia in the Russian royals, leaflets on genetic screening and wall charts on conditions such as Fragile X syndrome. The rows of plastic seats outside on the concourse are full of people. What does Super have to do to tear them away from their Eccles cakes? "A lot of people stand outside and read the displays through the glass. We don't approach people until they show an interest." But press him slightly, and he overflows with information, reeling off the odds on a genetic condition occurring - but then he did work at the Tote to pay his way through medical school in Johannesburg. His genial manner was honed by 12 years as the only paediatrician in Namibia, where he became interested in the high incidence of cystic fibrosis, leaving for Britain to study genetics in the 1970s. The shop offers information and referrals only, he stresses, the terms of its funding forbid counselling (and perhaps the first day of a holiday is not the best time anyway).

9am A girl in PVC trousers is taking notes. She is doing an A-level project on cystic fibrosis and her GP dad has driven her out to look at the exhibits. "It's more up-to-date than what we have in the surgery," he says admiringly as Super takes them into his office to look at videos.

ÖйúAƬ

9.30am The Orlando flight is delayed and a fractious family of six chunter in. Super attempts to guide the children to the screen that is belting out the Sickle Cell Rap, courtesy of the Notting Hill carnival ("Dey may be tired but it don't mean dey lazy, don't tease, let's make them feel at ease..."), but the two boys make a beeline for the touch-screen display whose first question is "Are you male or female?" Their mum watches as dad wanders off. "It's good, innit. Well, it's free."

The boys jab at the screen - what colour is your hair? Can you roll your tongue? - as Super pads up. "Are you the only one with ginger hair?" he enquires of the youngest. "No, there's my auntie in London." Super begins to explain why it is that the boy's dad has brown hair when mum interrupts: "That's not his real dad, that" and the toddler crawls off on to the concourse. But mum is gripped by the mysteries of hair types. "You know coloureds? Well, my brother, he's white and his hair's like theirs, all curly. Why's that? It drives him mad."

ÖйúAƬ

9.45am A girl in sportswear and white nail varnish wanders in. At the sickle cell display she answers the questions: "Should the younger sister of a girl with sickle cell be allowed to have the test for the disease?" with a firm yes. "71 per cent of other visitors agree with you," flashes up on screen. She smiles.

Meanwhile, Mum is huddled over the Fragile X display with Super. "It turned out she had a special interest," he says. "The eldest boy has a learning difficulty and she was wondering whether it was genetic."

10am The nail varnish girl is back, with her mum, a cheery Cheshire lady. She explains that her daughter had a spontaneous mutation of spherocytosis - similar to sickle cell in that it affects white blood cells - and her enlarged spleen was removed when she was four. If she has children they stand an even chance of inheriting the condition. "She's going for genetic counselling, of course," affirms her mother. The girl inspects her nail varnish.

11am The Orlando flight has left and there is a bit of a lull. Then a child throws up outside while being dragged along by his mum, creating a pungent barrier to further visitors. Super stays calm. "They're always cleaning the floor. It won't be long."

ÖйúAƬ

It is now nearly noon. "I'm hungry," wails a little boy by the door, dragging on his dad's arm. "Yes, MUMMY," he says, glaring at the crop-haired woman who is absorbed in "What is genetic counselling", "I DO think we need something to eat."

She moves to the Russian royal family. Dad's face contorts. "Leo, will you go and tell Mummy we're going to get something to eat." She reads to the end of the display before leaving. "I think she's a teacher," says Super. "She'd have spent ages if her husband hadn't been bothering her." He ticks them off on his chart. Sixty visitors so far - "if the Body Shop had 60 customers they'd weep!" - mainly young adults, more women than men, as usual.

2pm The concourse is emptying. A pony-tailed dad listens while the unflagging Super explains the origins of cystic fibrosis. "We're off to Spain in an hour," he says, wrapping his arm round his son's shoulders.

2.30pm The Gene Shop shuts. Eight thousand people have visited it this year, and Super is evangelistic about the growing need for such "high street" sources of unbiased information. The funding runs out in February. "But we want to stay open for four or five years. At least," he says, "until the Human Genome Project ends."

ÖйúAƬ

Kate Worsley