You can't choose your family, but you can choose your friends. So what do young people consider important when they choose friends? And what do they expect from a friendship? Vanessa, aged 14, Jasmine, 13, and two boys: Samir, 14, and 13-year-old Jack talked to 0-19 about friendship, and what friends are for.

Some people make friends more easily than others and you have to put yourself out a bit to make friends. "If you're lucky people will come to you, but on the whole it's up to you to say hello and find out what people are really like and whether you can be friends or not," says Samir.

So what do young people look for in a friend? Trust and loyalty are important qualities. "You want someone who can keep secrets so that you can tell them something and they won't blab it out to everyone," says Jack. Honesty works both ways: "I want to feel that I can be myself, and that I don't have to hide stuff," says Samir.

Being able to have a good time was most important of all. "You don't want a friend who is trustworthy but boring, you want to be able to have a laugh with them as well. At our age I think fun is the number one thing. You've got to feel the same way and share the same sense of humour or it just doesn't work," says Vanessa.

But friends are there for the bad times as well as the good. "You expect your friends to stick up for you if someone beats you up, and to help you through things," says Jack. You also expect them to keep in touch by mobile, text and e-mail. "When we get home we just log onto MSN [Microsoft network]. You can have much better conversations out of school," says Vanessa.

As well as being compatible on an individual basis, friends were expected to share the same group identity. "In our school there are townies, skate bums and goths and none of them mix with each other," says Jack. The only exception, they say, is if the friendship pre-dates the group identity. "Jack's a townie - he likes pop and R'nB and sports clothes. We're all skaters, but the four of us get on because we've known each other since primary school, and it didn't really matter then," explains Samir.

The children agreed that there were definite gender differences in friendship. Girls tended to have more "best friends", whereas boys, it seemed, had larger groups of friends, preferring not to depend on one particular individual. Having friends of the opposite sex was common, and they felt this had become easier from secondary school age.

Vanessa gave the example of her nine-year-old brother. "If you mention girls to him, he'd just say 'yuk'. When you're younger you stay with your own sex, but now we're more mature it's OK". However, all four agreed that it was much easier for girls to have friends who were boys than the other way round. "If boys hang out with girls too much, then they just get called gay. I can think of some boys who'd like to have friends of the opposite sex, but they're scared they'll get picked on," says Jasmine.

During the discussion the conversation returned several times to the subject of bullying. Getting picked on and being bullied is a major concern for these young people, and a barrier to friendships. "Bullies can get you to break up with your friends. They say things to you such as 'we don't like that person, and if you're friends with them we'll beat you up'," says Samir. "If a bully decides they don't like someone, then other people are scared to be associated with them, so they stop being their friends," adds Jasmine. The young people agreed that being without friends will make you an almost certain target for bullies. They gave the example of a younger boy in their school who was always on his own and had no one to talk to. "He seems really shy. He's always reading books at lunchtime, and the bullies have started noticing him. They throw things at him and kick him and call him names," says Vanessa. But they felt it was hard to help him. If they tried to make friends with him it might be construed as patronising, and they felt it was pointless to enlist the help of their teachers.

"Teachers will sort you out if you have trouble with your friends, but they ignore you if you haven't got any," says Samir.

It was clear that the young people expected to receive more day-to-day support and understanding from their friends than their parents. They felt it was especially important, as teenagers, to be able to rely on this and were more likely to tell friends than parents if they were in trouble. "There's always a certain level of taboo with parents, but your friends aren't going to be shocked," says Samir. Friends are far more likely to understand the ups and downs of being a teenager, which meant the young people were more inclined to seek out the company of friends than family.

"At our age, when you're having mood swings, it gets much harder to be with your family. Mood swings can make your family seem really horrible, so you want to spend more time with your friends. They know about it, because they're all going through it too," says Jack.

Young people have high expectations of their friends to provide them with support, and when they are let down it can hit hard. "When things go wrong with your friends, it's worse than when things go wrong with your family. At this point our friends are really, really important to us.

You've had your family all your life, and if they're mean to you, it's like nothing new, you're used to it. But if you're not getting on with your friends then it's much worse," says Vanessa.