Teachers are the only people who risk being misunderstood when they talk about "my children". Do they mean the scores or hundreds in their professional care? Or the smaller brood at home? And which come first? Many people assume teachers' offspring have an easy educational ride. They breathe literate, numerate air from their earliest years, are reared by experts in behaviour management and - in the unlikely event of their falling behind academically - have a tutor on tap at home.
But things are not always so simple. When 39-year-old Marie Kerr (not her real name) embarked on a PGCE course three years ago, she promised her two sons that once she qualified she would have more time for them and be less stressed. Now, working full-time as a class teacher in a demanding north London primary, she feels she told them "a terrible lie". She says: "I have about two hours less each day for them than when I was working in an office. My children have definitely suffered."
She gets up at 5.30am to do preparation and marking before her sons, aged 13 and nine, are awake. She leaves home before they do, and returns after 6pm. "By the time I've had a quick tidy up and made the tea I'm exhausted," she says. "I feel huge guilt that I'm not supporting my children in their education as I should be, with their homework, with school trips, or if either of them has a problem."
Time is not the only issue for teacher parents. Some find that their children's teachers feel threatened by their insider knowledge. Anne Barnes (not her real name) teaches at a primary school in Knowsley. Her 10-year-old daughter, although now "quietly confident", was not happy at her previous primary. "We'd have been a lot better off without the teacher label - if I'd been just mum," she says. "From the start she was put in top groups, higher than she should have been. I found myself going in saying that the work was too hard, the homework was too hard, because she is dyslexic. Gradually, she was matched a lot better with her ability."
Ms Barnes, like other teachers, finds some of her daughter's teachers defensive when it comes to dealing with a fellow professional. "I once wrote a note to a teacher asking if I could keep her reading book another day. She thought I was questioning her techniques and wrote a long letter back saying she'd been teaching for 30 years, and so on. I was only saying I hadn't had time to read with her last night. The teachers who give me difficulty are those who lack confidence."
Harriet Smith (not her real name), a teacher and single parent of six-year-old Ella, has had similar responses. "As a teacher, you are on the defensive sometimes, and I can feel Ella's teachers doing that with me. I am a teacher, but with them I feel like a parent. I am quite in awe of them. I once offered to help out for an hour on Friday mornings, but they never took me up on it."
Other teachers, inevitably, find they know their own children's teachers professionally, even if they are in a different school. Headteacher Ruth Ejvet's daughter, six-year-old Amy, goes to Wellington primary school in Waltham Forest, where Janet Pidgeon is head. "I knew Janet's reputation as a head and through the heads' union," says Ms Ejvet. "I'm 100 per cent supportive. But I'm realistic, being a teacher, and Janet knows that if my daughter were to have a teacher I considered not up to scratch, I'd be there, tackling the issues."
Not all teachers take the same view. "I hardly had time to notice their school," says one former primary head and mother of three. "Teacher parents always feel they have to defend the children - but are very aware of the strains the teachers face, especially the head. I couldn't bear to criticise my children's school, even though I was well placed to do so. The children's needs can get submerged."
The education of teachers' own children highlights some of the contradictions of the system. Maureen Freeman, 49, is key stage 1 co-ordinator at Jessop primary, a 270-pupil school in Lambeth. Her son, Sam, 13, left the school shortly before it went into special measures in June 2000. But he'd done well and been happy at the school. "There's no way I would have kept him at a school I wasn't happy with," she says. "It's much easier to work in that situation than to put someone who belongs to you through it."
The question of how the children progress can be particularly fraught. Susan Masters (not her real name) is a teacher in a Yorkshire secondary. Her 14-year-old son is a "third-generation dyslexic"."I'd love to be able to say, 'As long as he's happy, I don't care'," she says. "But the reality is that he has a very good standard of living and he's going to need a good job to maintain it.
"At the moment I'm fairly content with the way things are going. I think he'll probably end up in the C stream but, professionally, that's where I'd put him. I have to be aware that I can be an over-anxious mother, and trust in the professionalism of others. That's what I expect from parents and I must try to do the same thing."
While it's difficult for any parent whose child has troubles at school, it's arguably worse for teachers. Marie Kerr's sons' behavioural problems cause her pain - as a mother and as a teacher. "Both boys have mentors, which makes me feel I'm failing as a parent," she says. "I spoke to colleagues, about how their children had been, and found it wasn't unusual for teachers' children to be the ones who are misbehaving in other schools. But I'd never talk about any of this to the head or the senior management team, because it would reflect on my professionalism.
"At one point, my younger child was going to be referred to the behaviour unit I work with. I thought I'd be torn apart as a parent and as a teacher. Then I spoke to the head of the unit and she said he wasn't severe enough, and there was an 18-month waiting list anyway."
Teacher parents can, of course, use their professional knowledge to intervene in their children's school lives. Paul Bennett, 45, is head of Gorsemoor primary in Cannock, Staffordshire. His two boys, 14-year-old Luke and 12-year-old Jamie, attend the local high school. "I try not to interfere but I'm aware of odd things they say about what goes on, and read between the lines," he says.
Three times he has raised minor concerns with the school, by letter, and had satisfactory responses. "There was an issue recently where I considered communication from the school to us very poor, and I've written saying that, as someone in the same profession, I believe this should be looked at. But I don't want staff involved with my children to feel under any extra pressure."
Stuart Ayres, 43, has for the past seven years been head at St John's C of E primary, a 424-pupil school in Essington, near Wolverhampton. Until recently, his two children, Alistair, 13, and Rosie, 12, were pupils there. Their mother, Jenny, is finishing her PGCE at Wolverhampton University.
"It was successful but quite difficult, particularly for Alistair," says Mr Ayres. "It was not easy to be the head's son and maintain any credibility. And some things in the playground that wouldn't usually come to a parent's attention would sometimes be brought to me by a member of staff. I think it was difficult for them, because the parent they were having to deal with was their boss."
It was difficult for Mr Ayres, too, when his roles as parent-head blurred. As his own children approached key stage 2 SATs, their friends' parents asked him informally for hints and tips on what he thought would be in the exams. Some were surprised, too, when he did not enter his children for tests for selective schools in the area. "I didn't really want to enter the debate. But my own choice was for them to go through the comprehensive system. It's defining the boundary between your personal beliefs and the demands of your job that can be difficult."
Now that Alistair and Rosie are in the local high school, Mr Ayres tries to be around for them, although the demands of his job make it difficult. "My wife's always there reminding me that I've got to put my own children first wherever I can. Although I must say, with some regret, that often I have to put the school first.
"My son had a parents' evening recently, and I arrived late. I ended up ringing my wife on her mobile to try to find out which queue she was in. It was a farcical situation and I ended up only seeing the PE teacher with her. Then the guilt comes in."
But when he does get to talk to his children's teachers, he thinks he's more understanding than the average parent. "As a head, you're often the middle man in a parentteacher dispute. I think I'm extremely reasonable as a parent.
"I do enjoy a good relationship with both my children, and certain times are definitely just family. I might do a 55-hour week but on Saturday afternoons I'm at the football, and I'm pleased that my son and my daughter both come with me. We've all got season tickets."
Ruth Ejvet is head of St James C of E primary, a 210-pupil school in Enfield. Her six-year-old daughter, Amy, attends Wellington school in the neighbouring London borough of Walthamstow. "I helped out in the school before I was a head, so the teachers got to know me as a supportive parent rather than someone looking on from a distance and criticising, which helped.
"I do ask questions that have a different slant from your average parent. I'll ask how she's doing with different parts of the maths strategy, whether the ICT system is up and running and how much access to computers she's getting. But they're respectful of that because we have a good relationship.
"In the Ofsted parents' meeting, I used Ofsted-speak and jargon, because it was beneficial to the school. I spoke to the Ofsted team as a professional, I knew what I was talking about and I was happy."
RUTH EJVET is adamant that her child comes first. She says a teacher friend's experience of not speaking out for her bullied child - with resulting emotional scars - showed her that she had to champion her daughter. "Amy comes first. Understanding the teachers' situation comes second. I would not accept my child suffering, or not being encouraged to reach her potential."
As a head, she has tried to create a parent-friendly culture for herself and her colleagues at St James. "I encourage all teachers who are parents to go to their children's school events - an assembly or sports afternoon. One even had time recently to deliver her child to university. I've built in a budget and I've built in a philosophy. As teachers we know children are desperate for parents to come to assemblies and other events. But we have been guilty of that offence - not being able to turn up and support our own."