Is it true that oysters are an aphrodisiac? My question boomed across the hushed gentleman's-club atmosphere of Bentley's Seafood Restaurant and Oyster Bar. 'It will take a couple of weeks and several servings. Oysters have zinc trace elements which are very important for a healthy prostate gland which secretes hormones that are important for maintaining an erection,' came the exhaustive reply - not from the waiter (though it would be fun if Bentley's waiting staff were versed in the properties of the dishes they were serving), but from my lunch companion, sexologist Professor Ng Man-lun. Professor Ng is a psychiatrist specialising in the study of sex and a lecturer in the Faculty of Medicine at Hong Kong University. He also treats patients with sexual problems and is a motivating force behind the Hong Kong Sex Association, which aims to remove sexual biases and improve sex education. Perhaps not surprisingly, he has earned the accolade Dr Sex. Safe eating was very much part of our lunch deal: Professor Ng was taking no risks when dining with a new lunch partner and in an unknown restaurant. 'I very rarely eat uncooked seafood. Cooking kills any viruses in the seafood,' said the professor, so we increased our zinc elements (not destroyed by cooking) on six lightly poached Scottish oysters. Compared with the exciting, slippery let's-live-dangerously texture of the raw oyster, the cooked texture was bland, though Bentley's provided the means to spice things up, with a Tabasco bottle sitting enticingly on the table. 'I don't like eating spicy things but spice can be an aphrodisiac as it stimulates the sensations and has an immediate effect,' said Professor Ng, quite deadpan. 'You can buy local medicines which contain spicy oils that are applied to the sexual organs as it makes them feel hot.' As my eyes swivelled to the Tabasco bottle, Professor Ng added: 'Some people do apply spicy sauces to their sexual organs but I don't recommend it, as the spice will cause muscle dilation and can lacerate delicate tissue and cause inflammation.' Still discussing my quest for the ultimate aphrodisiac, Professor Ng said most dishes that resembled sexual organs were reputed to have aphrodisiac properties - but it was all psychological. Though Bentley's imports 80 per cent of its seafood twice-weekly from European waters and places a premium on serving fresh good-quality meals, my eyes were drawn to other dishes. We spurned the fishy starters of smoked salmon, mussels, caviar and herring, and various salads and soups, for a dish of cold asparagus with a vinaigrette dressing. The phallic green spears of asparagus were pleasant and had a slight crunch. My mind was racing. 'Food is important for sex, as sex is a bodily activity like any other function and the body must be healthy. Thus, it is good to eat a well-balanced diet of fresh, nutritious foods,' he said. Bentley's offers the traditional British staples of Dover sole and fish pie but also has a variety of international fish dishes such as Maine crab cakes, prawn curry and Australian scallops, as well as egg, pasta and meat dishes such as steak-and-mushroom pie, duck breast and roast lamb. 'Seafood is a healthy choice as it has a low saturated-fat content and contains iodine which stimulates the thyroid gland which affects sexual functioning.' With Professor Ng's advice in mind, I chose fish pie, which was tremendously comforting and had substantial chunks of fish and prawns in a creamy wine sauce topped with cheesy mashed potato. Professor Ng plumped for the grilled Loch Fyne kippers but found them a little salty for his taste, declaring: 'Too much salt increases the blood pressure.' Alcohol in moderation (Bentley's has a reasonable selection of mainly French wines and a few by the glass) was 'an important part of foreplay' but he issued the familiar warning against excess. Many of Professor Ng's patients come to see him with problems of sexual dysfunctioning - and again he said most of them are psychological in origin. He teaches couples sexual techniques through diagrams and gives them exercises to practise at home. With visions of Professor Ng handing out videos of the raunchy food film Nine And A Half Weeks, I whispered over the linen-covered table: 'Can food be part of sex therapy?' By 1pm, the basement restaurant was full and it did not seem the type of conversation business people - let alone the fish in the watercolour paintings lining the walls - were used to overhearing. 'I wouldn't suggest it but then neither would I object. There is a relationship between food and sex. People who love food love life, but also people who are unhappy with sex will substitute food for sex.' The wickedly fattening puddings - toffee-and-banana crumble, bread-and-butter pudding, sherry trifle and sticky toffee pudding - could not tempt the strong-minded professor: 'Desserts are fattening, I don't eat sweet things.' But we did manage to finish lunch with a couple of stimulants - tea and coffee. It seems the life of a sexologist is a busy one. 'I have no time to cook and I am not that interested in food. I eat a lot of fast food but I would come here again,' he said. The bill for lunch came to $666 for two, with the six poached oysters bumping up the bill by $186. Nothing that much fun is cheap. Bentley's Seafood Restaurant and Oyster Bar, B4 Basement, Prince's Building (Entrance Statue Square), Central. Tel: 2868-0881. Open: noon-2.30pm, 6pm-10.30pm, Mon to Sat