For the past eight years, photojournalist Stephanie Sinclair has traveled the world gaining intimate access to families and child brides to document the practice of child marriage.

The phenomenon of child marriage is far more common than many people think. PBS NewsHour reports that more than 50 million girls under the age of 17 are already married in developing countries, and 100 million more are expected to marry in the next decade.

Sinclair, whose photographs were recently featured in "National Geographic" magazine in a story called "Too Young to Wed," sat down with PBS NewsHour correspondent Hari Sreenivasan to discuss her work.

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"But there's other -- there's traditional issues that are involved. There are -- religion has always been a justifier in almost every situation I have been in, regardless of whether it was Islamic or Hindu or Christian weddings. There was some sort of justification why it was allowed to happen." -Stephanie Sinclair, "National Geographic."

"I spoke to an 8-year-old girl named Tahani who is sexually active with her husband, and -- who's in his late 20s, early 30s -- and she didn't have any idea how babies were made, about anything." -Stephanie Sinclair, "National Geographic."

"And I had actually one mother in Afghanistan who -- I photographed the engagement of a young girl, 11-year-old girl, to a man in his 50s. And the mother was crying and telling me, you know, "We don't have enough food to feed the rest of our children. We're selling our girls." -Stephanie Sinclair, "National Geographic."

1. What is a child marriage?

2. In what region(s) of the world are child marriages occurring?

3. Is child marriage legal in the United States?

1. Why are child marriages more prevalent in developing nations?

2. Do you think child marriages should be illegal? Why or why not?

3. Do you think culture or religion should play a part in child marriages?

4. How do you think it would make you feel if you were forced to marry as a child?