Is it a mistake to talk about your children at work?
If you had to make a list of topics not to talk about at work, you'd probably include sex, money, religion and politics. And they might be closely followed by mental health or (dreaded phrase) "women's problems".
But would you include children in that list?
As the mother of a "challenging" boy, it's a pertinent question for me. When my mobile rings at work and it's After School Club reporting on his latest misdemeanour, how much do I reveal to my colleagues?
So let's put the question out there: is it OK to talk about your children at work?
"Not if you want to get on," said a friend whose husband works in one of the country's top corporations, and who has observed the behaviour of its senior staff over many years.
And workplace psychologist and author Jessica Pryce Jones is in no doubt about the danger of being too free with the details of your home life, especially if your children are creating glitches in its smooth running.
"Being at work, you want to show as little vulnerability as possible, because when you show vulnerability, you're weak, and when you're weak, somebody else stronger than you takes position in the pack," she says.
"I think you have to be a very strong character in a corporate world, I really do."
So here's the follow-up question for working mothers: do women have to be stronger than men? Are they judged differently?
"Absolutely," says Jessica Pryce Jones. She believes that if men talk about their children in the office, it reflects positively on them. They're seen as caring fathers. But, she says, it's not the same for women.
"I just could not talk about my children in the same way, knowing that it would not be perceived as a strength in me. Just knowing that it would be perceived as a weakness."
The parenting website Mumsnet backs up the view that there's a delicate balance women must strike. Its advice to mothers returning to work finishes with: "And remember, the golden rule is: don't talk about work all the time at home and (probably more important) don't talk about your kids all the time at work."
The difference in the way men and women are perceived kicks in as soon as you have a child, let alone whether you talk about it, according to recent research.
When the Fawcett Society, which campaigns for gender equality, ran a poll earlier this year, it found that 46% of those who responded believed that a woman becomes less committed to her job after having a baby. The corresponding figure for men was 11%.
And when the question was turned round, nearly a third of the people polled thought that men actually become more committed to their job after becoming a father.
In the jargon, it's the "mummy penalty" versus the "daddy bonus".
Tamara Box is a partner at the international law firm Reed Smith, and she also chairs Cancer Research UK's Women of Influence initiative. While she agrees that women are subject to bias in a lot of ways, she is adamant that this shouldn't stop them from being themselves because, in her view, that doesn't make business sense.
"Telling women you should button up about your kids or pretend you don't have any, or never mention if you have to leave for childcare reasons, you know that is not the right answer," she says, "because it's bad for our business.
"Those women will eventually decide, 'This isn't the right place for me,' and they'll leave."
And not everyone agrees that this particular issue should be viewed through the lens of the battle of the sexes.
"I do think it gets stuck as a gender thing," says Ailie MacAdam, managing director for infrastructure in Europe and Africa at the engineering and construction company Bechtel. "It's about the way your mind works."
Within her own team, she explains, some people find a bit of non-work chat useful at the beginning of a meeting, but others see it as an irritating, even stressful, distraction. And in her experience, that preference isn't dictated by gender.
Like other companies, Bechtel runs unconscious bias-awareness training, and Ms MacAdam says that helps to bring the issue into the open: "It's important to create an environment where you can say, 'When I talk about my children, what do you think of me?' It's healthy to have that conversation."
Not only healthy to have that sort of openness, argue some, but essential for the smooth running of many businesses. The modern workplace is more informal and tolerant, asserts Tony Franco, a brand consultant who works with the marketing departments of many companies.
He says revealing something about yourself, and the kind of person you are, is an important part of that: "Obviously, the key thing you need to do at work is to create good relationships with all your work colleagues, create a rapport, so you trust each other, so you know each other. That's really quite fundamental, particularly if you're working in teams."
Tamara Box agrees. She believes that far from undermining your professional image, the revelation that you have children can be a useful way of building relationships with clients as well as colleagues. And as the mother of a 10-year old son, it's one of the tools she deploys in her business life.
"There are a number of ways that one can connect with others and that's a lot of what the workplace is about," she says.
"You are most effective when you're connecting and so for me that may be a point of connection. But it may not be."
That caveat is important. Not every office is the same, but as Ms Box points out, it's a bad idea to talk about anything endlessly if it doesn't interest your audience, whether it's your weekend game of golf or your amazing offspring.
Proud parents take note.