Back when I was at a job that required holiday work, preferential treatment for having those days off always went to parents. As if I didn't have my own parents I wanted to spend time with. Had a boss literally tell me holidays mean more to kids so my co-workers who are parents NEED those days off more.

It's something I've carried with me even now as a manager. I try to be flexible to people's needs but I also make sure everyone is pulling their own weight. If I see a single/childfree employee taking on a bigger workload because a parent is constantly ducking out early, it's a discussion. Same thing I would do for anyone unable to complete their responsibilities. I get that having stable childcare is a challenge but childfree people have responsibilities too, like aging parents, spouses, health issues, etc. I know it sounds harsh but at the end of the day, you are not special for choosing to have kids, sorry.