Women told me that they hid their pregnancies until well into the third trimester, wearing loose-fitting clothes to avoid telling their bosses or venture-capital funders that they were expecting. Once they had kids, some told me they simply never discussed them. If they had to deal with a child-related issue, they lied about why they were leaving work.

One woman told me she worked on a team of men, all of whom were fathers. Pregnant with her first child, she noted that none of the men ever talked about their children, and she assumed she shouldn’t either.

The general sense is that everyone should adopt the polite fiction that after the first several months of leave, the child disappears into a void from which he or she emerges for viewing and discussing only during nonworking hours.

Reinforcing this point, women professors at my university told me that when they were more junior, they made it a point never to put pictures of their children up in their offices.

These are, however, mostly anecdotes. And I often argue in my writing that anecdotes are not enough. Thankfully at least some research exists on what you might call “secret parenting,” even if much of it is more qualitative than strictly data-based. One example is a 2014 paper in Gender, Work & Organization based on interviews with 26 mothers of small children.

The women returned again and again to the issue of secrecy: “Hiding being a mother and engaging in strategies for secrecy were ubiquitous themes in our interviews,” the authors wrote. “Many women who had gone back to work tried to conceal that they had small children or pretended that their children’s interests were of little importance to them.”

Read: Parenting looks nothing like what the experts say

Why would people do this? Why pretend kids are of “little importance”? When work and parenting seem at odds—because our culture tells us they’re at odds—mothers and fathers feel forced to demonstrate their commitment to one (the work side) by minimizing their concern for the other (the parenting side). They do not want their bosses to think they are anything other than 100 percent committed.

To draw from personal experience: I was an untenured assistant professor when I had my first child, and I went back to the office for my first meeting when she was just a couple of weeks old. Yes, I did that in part because I wanted to get out of the house and see other adults. But I was also worried that if I didn’t get back to the office fast and show my face, my senior colleagues would assume I wasn’t planning to take my job seriously going forward.

Hiding your kids at work is no easy task. Even if you skip baseball games and school plays and parent-teacher conferences, your kids will sometimes get sick. Child care will fall through on occasion. Some of the women in that paper I cited above reported that they had feigned illness when their child got sick, because taking a sick day for themselves seemed acceptable, but taking one to nurse a child did not.