As caliotter mentioned, this is not a phenomenon specific to nursing, I think in all areas, those with children are perceived to have a higher priority with regard to maintaining schedules, getting time off for sick kids, etc. I think you're well within your right to speak up if you see this treatment and remind a coworker or management that your time is no less important because you don't have children. When I was working in a different field, my husband was home with our kids so I wasn't impacted by sick kids, snow day at school, school vacation, etc. However, I had many coworkers that considered it a free day off if their child was home sick. Wouldn't use vacation time, sick time, etc. would just stay home. Clearly this was a different work environment, people could catch up on things on another day. But, some people definitely took advantage and it was frustrating to those of us that didn't use this "benefit", management can run things well, or poorly, best you can do is hope yours makes things equitable.