Why is the word 'childless' unacceptable? It screeches of loss or tragedy, even sterility. At best it's offensive to those who have chosen not to have children, and at worst it's grotesquely insensitive to those permitted no choice.
After divorcing in my late twenties, I was glad I didn't have children. For a time I believed I didn't want kids at all. But in my mid-thirties when my younger sister got pregnant, I absolutely struggled with the choice.