Janice Chaka had spent her lunch hour organising a surprise cooking class for a close friend who was visiting from out of town. After getting stuck in traffic on the way back from the venue she ended up back in her office five minutes’ late from her break.

“I got asked a lot of questions and I had to stay and do extra work,” she says. “But I know if I’d been late back from taking my kid to the doctor, that wouldn’t have even been an issue, in fact I probably could have taken the whole afternoon off.”

That happened a decade ago, when Chaka was working in human resources in Guadalajara, Mexico. But the experience conformed to a pattern that she says was common as she forged a career working for Fortune 100 companies in the US and Mexico throughout her twenties, both as a singleton and while in childless relationships. Colleagues with children were also prioritised when it came to taking their preferred vacation dates, she claims, while fellow single or childless workers struggled to get time off to care for elderly relatives or were asked to go on more frequent business trips.

“The assumption is that you can drop everything or that you don’t have a care in the world,” says Chaka. “Actually, as a single, life is more expensive, you have to run all errands yourself and you don’t have someone to fall back on financially if things go wrong.”

While it’s tricky to nail down concrete statistics that prove how much singles might be being indirectly penalised in the workplace, a recent UK study of 25,000 workers found that two thirds of childless women aged 28 to 40 felt that they were expected to work longer hours. Growing numbers of workers, academics and analysts are documenting the issue.

During research for his book Going Solo, Eric Klinenberg, a professor of sociology at New York University interviewed hundreds of single people in Europe and America and discovered “there was widespread perception that singles became the workhorses in corporate offices”.

“I met countless workers who complained that their managers viewed them as always available for late night and weekend assignments, because they didn’t have children or spouses,” he says.

“In a few cases, I met women who said that they had been denied raises that they deserved, because their managers believed that they didn’t need the extra money as much as colleagues with children,” adds the author.

Bella DePaulo, a professor of psychology at the University of California, Santa Barbara, explores the phenomenon in her books and studies, and coined the word “singlism” to pin down the stigmatisation, negative stereotyping and discrimination against singles that she believes is widespread in the workplace and society at large. She argues that many employers are missing a trick when it comes to single employees, who, far from being lonely and isolated, are actually more likely to be actively engaged in their communities and have strong relationships with friends who “feel like family, even if they are not family in the traditional sense”.

So, what should single workers do if they feel they’re being singled out because of their personal life choices or situation, yet don’t want to jeopardise their careers and reputations?

“Don’t bitch and moan about your particular circumstances,” is the first advice dished out by UK-based business mentor David Carter.

He argues that “the answer is in the crowd.” Single colleagues should consider clubbing together, he says, to identify and propose changes to company practices that might benefit the organisation more widely, while at the same time demonstrating their own problem-solving skills.

Other business leaders argue that offering equal latitude to all employees in terms of work schedules is easier said than done.