MANY parents lose sleep over thoughts of their offspring staying out late, smoking, boozing and getting up to no good with members of the opposite sex. For years it seemed that Muslim parents could rest a little easier. The lack of alcohol-free nightspots has made going out tricky for their teenage children, who are banned by their religion from drinking. But that gap is rapidly being filled. Shisha bars, where people smoke hookahs on heated outdoor patios, have mushroomed since a 2007 ban on smoking in public places. A study of 133 local authorities by the British Heart Foundation (BHF) found that the number of bars had risen from 179 in 2007 to 556 in 2012. Phil Johnson, one of the founders of the National Association of Shisha Bar Owners, reckons there are many more. Some can accommodate as many as 400 patrons. Smoking shishas is common in Arab countries such as Egypt. But British Muslims mainly trace their origins to South Asian countries such as Bangladesh and Pakistan where it is rarer. In Bradford, one city where shisha bars are flourishing, a fifth of the population is Pakistani. Fewer than 1% are Arabs. Shisha lounges appeal to Muslims of both sexes who are too devout to go to clubs but not devout enough to hang out at the mosque, says Naweed Hussain, a political activist in Bradford. There, and in cities such as Birmingham, the clientele is predominantly Asian. In London and Oxford patrons are a more mixed bunch. But even in Birmingham non-Muslims are keen. A decade ago there was much worry about Asian Muslims living "parallel lives" that rarely intersected with whites. Shisha lounges are an exception. Few serve alcohol. In the Havana Shisha Lounge in Birmingham, piles of fruit, waiting to be juiced, sit next to lavishly iced cakes and tubs of ice cream. Milkshakes are a common accompaniment to shishas. Young Muslims relish sickly flavours of tobacco such as fizzyberry, gummy bear and blueberry-vanilla much as non-Muslims savour pineapple Bacardi Breezers. Smoking them is cheaper than other suitable activities, such as bowling. A shisha costs about £10 ($16); four or five people can share one for an hour. Fans argue that, unlike getting drunk, smoking shishas is not haram (forbidden). At worst, it is makruh (detested but not strictly prohibited). Ibrahim Mogra, a senior member of the Muslim Council of Britain, disagrees. The molasses-soaked tobacco used in water pipes damages people's health (the BHF says that one hour of shisha smoking is equivalent to puffing on 100 cigarettes), so shishas are haram. He also frets about what goes on besides smoking: "I dread to think of them becoming the equivalent of bars and pubs where anything and everything goes." Boys and girls may be out of their parents" sight but not out of God's, he cautions. Mr Mogra's fears are not entirely misplaced. One young man who sometimes works in his father's shisha bar says that customers occasionally smuggle in alcohol from a nearby supermarket (his father does not know). Girls come in droves and boys flock there to meet them. But those worried about the integration of British Muslims ought to find all this reassuring. Muslim teenagers are as rebellious and amorous as young people everywhere.