Photographer Stephanie Sinclair has been photographing the issue of child marriage for 13 years. Her work on the topic was featured in the 2011 National Geographic magazine story “Too Young to Wed” (which is also the name of the nonprofit she founded in 2012 that advocates to end the practice). I wondered how Stephanie has sustained her coverage for so long—if she’s kept up with the girls she’s photographed, who she surrounds herself with, how the issue has evolved, and if she ever needs to take a break.

Then you take the experiences of the relative handful of girls and survivors I’ve met and then realize … with child marriage occurring in more than 50 countries