There is a difference
Someone will often ask me to explain the difference between a person who is childfree and a person who is childless. I’m happy to direct people to my book for further information. It is one of the most common questions I get from people in person, and online readers. Without quoting my book directly, I will summarize it here as best as possible.
A person who is childless feels the lack of having a child in their lives. They might have tried to conceive children without success, not knowing if it is because of a medical reason. Others may be childless because they cannot conceive children and have been told so by their doctors.
A person who is childfree is not “childless by choice”. Less means lacking in something. The choice not to have children is represented as a free choice. So, someone is not lacking in having children.
For further information, there are great numbers of online resources available. My personal favourite which I would encourage everyone to check out, is Non Parents, where I have contributed some content.