writes that "You'd need to be mad" to share personal information with students in some schools. Another says that to reveal anything other than your favourite colour is to "open a can of worms of horrendous proportions".
Others argue that it is best for less experienced teachers to get really established before hinting that they have a life outside school. John Perera*, a student teacher in East London, England, has direct experience of this: "I told my students that I was married and had children, which I thought was innocent enough."
However, one naughty 13-year-old student shouted: "Eww, Sir, that means you had sex." He was clearly trying to derail the lesson and waste time.
"If I had said I was single, they would have said, `Oh, Sir, you haven't had sex yet, you're too ugly to pull'," Perera adds. "In a bad class almost anything can be used against you."
Perera, from Mauritius, has been the subject of intense curiosity from children because of his dark skin and foreign accent. "They are always trying to distract me with questions, they are constantly asking if I'm a Muslim, maybe because there are many Muslim students in the school. I'm actually Roman Catholic but I just tell them it's none of their business," he says.
But teachers of younger children seem to take a more relaxed approach: "You are much closer to your class and I think that there is no harm in revealing some things about yourself," says one forum contributor.
Suzie Clements, who lives just four minutes' walk from her school in London, is often spotted by students out and about at the weekend. They know which block of flats she lives in and can sometimes be found lurking around outside.
Although she is not in the habit of sharing things such as her birthday or details about any personal relationships, she thinks that what the students do know about her creates a sense of closeness and community. She attends karate classes at the same centre as some of her students, something she believes helps to establish an important connection.
"With the karate I think it's nice to have a shared hobby. There's a girl who is a carer for her mum - she comes to me at school and says, `We went to karate'. It gives her a connection with another adult."
Students have even seen her out with her partner, although they have never asked her about him. "There's a line no one's stepped across. It could be because they are of primary age (4-11)," she says.
Meanwhile, other teachers are positively enthusiastic about weaving themselves into a lesson - as long as it is for a distinct educational purpose. "The connections that have to be made to be successful in the classroom stem from opening up and bringing my students into my world," says Brent Smiley, who teaches social studies to 14-year-olds in Los Angeles, California.
"That is done with stories; stories about my life, my family and my friends. The end goal is to find shared experiences," he says. "In each case, however, at the core, there has to be a moral or lesson to be learned, that is the real goal."
This may be all well and good if you have a reasonably ordinary life. But what if your lifestyle, views and political allegiances are a little more exotic or controversial?
"I am lucky in that I am dull.there is never a huge amount of interest from students in my interests or hobbies," says inner-city English teacher and education author Phil Beadle.
"Where teachers have to be careful is if their lives are non-standard, or where they are youthful and pleasing of face. Here, student interest has to be managed. You do this by being professional and not divulging anything you think may affect their respect for you," he says.
So it's probably best not to mention if you are moonlighting as a stripper or directing porn films in your spare time. And if you really must keep doing it, don't get found out by advertising it on the internet.
However, even if teachers follow very ordinary pursuits now, some may find that their past comes back to haunt them. Sarah Green was working as an English teacher at an independent school in the North of England. But in 2008 she was suspended after it emerged that she had starred in a risque advertisement for industrial clothing prior to becoming a teacher.
This is, of course, very unusual, but for others there are more mundane problems. For example, despite huge steps forward in mainstream adult society, being a gay teacher can still be a big issue. Many gay teachers are not actively "out" to their classes. Some have never found an appropriate moment to mention it, others are afraid of the reaction they may receive from students and parents.
David Colwill, a biology teacher at a girls' grammar school with eight years' experience, has never told students that he is gay, mainly because they have simply never asked.
"Among the staff, the vast majority know I'm gay and they know about my fiance Jack. It's no big secret," Colwill says. "But I still haven't worked out how I would react to being asked by a student. I would like to think that I would be honest with them and come out with it. But if they put me on the spot, I might just end up saying, `You know what, I'm single'. It's not about personal embarrassment, but I'm catering to the least tolerant of the parents."
And he's not alone. Computer science and ICT teacher Cameron Akitt shares his interests in Star Trek and comic books with students, but wants to wait to become more established in a school before coming out to them. "If it comes up, I think I will be honest about it. I would rather be an open role model than an open rumour," he says.
But it's certainly not just about sexuality or personal tastes in television. Politics is also a delicate area, Beadle says. "In terms of context, it is sensible to be aware of the mores of the community you work within," he explains. "If you work in a Catholic school, don't express Satanist views as they can be unpopular. If you work in the independent sector, your deeply held and rational Trotskyite views are probably best left unexpressed."
Adam Walker, a British National Party (BNP) activist and teacher, resigned from his school in 2007 after he used a school laptop to claim in an online forum that Britain was a "dumping ground for the filth of the third world (sic)".
Membership of a far-right political party such as the BNP is not illegal for teachers, but the Department for Education (DfE) states that "performance and disciplinary procedures could be used if a teacher was teaching something inappropriate".
The NASUWT teaching union has campaigned to have BNP members banned from teaching, but the government now prefers for "schools to deal with it on an individual basis".
Although the classroom context is clearly the biggest decider for most teachers, what do the teacher trainers say on this issue? Are there any pitfalls for new teachers to avoid?
James Williams, lecturer in education at the University of Sussex, England, says: "It's a question of widely differing views. I've worked in schools where teachers bring in their new babies, while others wouldn't dream of doing this.
"It's for new teachers to think through what they are comfortable about and the consequences of what they reveal as a new teacher. In terms of giving personal information, the younger you are, the closer to the generation of children, the more reluctant you should be to give information.
"You need to build professional distance if you are relatively young. Otherwise they might think of you as a friend. It's easy to blur the line between teacher and friend."
And don't bother trying to be cool, he says: "Children are odd, the idea of teachers in their twenties doesn't exist for them. They feel there should be a divide between them and you and what you enjoy and like. On non-uniform day, students can be quite shocked at how the teacher dresses."
Williams also warns of the dangers of social media revealing rather more information to students than a teacher would like. Staff, he says, should be extremely careful to adopt the highest security settings, not to befriend students on Facebook and to be cautious about which photos they put up.
"You have to be careful with technology now, it may be doing things you don't even realise - for example, my camera was uploading all my photos on to Dropbox without my knowing."
Above all, it helps if you lead a clean and innocent life. After all, the DfE's Teachers' Standards state: "A teacher is expected to demonstrate consistently high standards of personal and professional conduct."
"The professional standards apply all the time and there are still teachers who don't understand this," Williams says.
Andy Jones, dean of the faculty of education at Manchester Metropolitan University, England, says that teachers can feel under pressure to reveal information about themselves in a way other professions are not. "Nobody would expect their bank manager to talk about their personal life, yet teachers are sometimes pressured into giving information," he says.
"Some NQTs (newly qualified teachers) come unstuck if they have got into a chummy relationship and then have to deal with bad behaviour. They have chipped away at their professional status by allowing that personal relationship," Jones says.
"Longer-standing teachers are much more embedded in the school structure and they are much more confident about handling these problems in the student-teacher relationship.
"With young teachers there's always a flurry of interest - they might look young and trendy; there's a sense of fascination."
It is a fascination that some teachers argue we should all harness. Over in Los Angeles, Smiley has no qualms: "There is not a day that goes by that I'm not sharing something from my home with my students," he says.
"It usually involves my own children and stories meant to amuse but deliver a message. Far from undermining a teacher's authority, I think it boosts it beyond measure by making us more human."
*Names have been changed.
Treading a fine line
How much should I tell my pupils about myself? A few top tips:
- Don't make friends with your students. This could lead to problems if you ever have to discipline them for something serious.
- Once you're established in a school, don't be afraid to reveal things about yourself, if they are relevant and useful to the lesson.
- Young, attractive teachers are vulnerable and students' fascination levels are high. Take a "less is more" approach.
- Be wary of inquisitive students: they may be trying to derail the lesson and waste time.
- Steer clear of discussing any strongly held political views (Communist or British National Party membership, for example).
- If you have decided to remain a complete enigma to your students, find other ways of forming human connections (end-of-term cakes, anyone?).