There are many reasons to choose to live child-free. Some very valid reasons are overpopulation, living with a smaller footprint on the planet, and not wanting to raise fodder for the war machine. Choose from these t-shirts and get the word out.
A yellow traffic triangle informs everyone who comes near you that you are a "Child-Free Zone." Wear it with pride and give the child-free by choice a face others can see and respect.