At my first university teaching job, the person who coordinated the teaching schedules asked me to teach at night. She said it would be too difficult for my married colleagues to come in at that time.

I knew which colleagues she had in mind, and none of them had kids. I declined. I think work should be about work, and all employees should have equal obligations to cover unwanted times. Marital or parental status should have nothing to do with it.

If married workers want their single colleagues to cover for them, there should be reciprocity – they should also be willing to cover for their single colleagues when they have places to go and things to do. Same for workers who are or are not parents.

I’ve heard many anecdotes about the unfair expectations placed on single workers or workers with no children (whether single or coupled). Personal stories are interesting and important, but as a social scientist, I’m always looking for more extensive, systematic data.

In the U.K., “Opportunity Now,” a group that “aims to increase women’s success at work,” conducted a survey of 25,000 people. The vast majority of the participants were women between the ages of 28 and 40. Opportunity Now describes that age range as critical for career development – “the danger zone where women are not promoted at the same rate as men.”

The size of the survey is a real plus. However, the sample is not a representative national sample. Instead, participants were recruited to participate in the online survey by email, social media, and the national press.

Many of the survey questions pertained to women who had children. Most interesting to me was a survey item about women who do not have children:

“I feel women with no children are expected to work longer hours than those who do not have children.”

Only 21 percent of the participants disagreed with that statement. Close to two-thirds (65%) agreed with it. The others said they neither agreed nor disagreed (or thought the question was not relevant).

Opportunity Now recognizes that women without children “have interests and responsibilities outside work,” including, for example, “caring for elderly relatives, social activities, community involvement and commitments.”

I don’t think any workers should be pressured to work more hours than their colleagues, especially if they are not getting any extra pay. They also should not be asked to justify the time off that is due to them. It shouldn’t matter whether they want to leave on time to care for an elderly relative or go home and read a book.

One of the U.K. survey participants noted that “women-friendly policies in the workplace are centered around mothers.” But single women who do not have kids “also have outside interests which they want to pursue (which does not include being regularly asked to cover for colleagues working part time or from home).”