Rasmia Ahmed Emam was 17 when she was married to a 50-year-old stranger.
"My family is a big one so I had to sacrifice to support them," she said. "My dad went to a marriage broker to find a rich husband for me and she told us she had a Saudi man. He came and seemed to like me and gave my parents the money to build a roof on our house."
The desperation of poor families combined with an acceptance of child marriage has created opportunities for unscrupulous marriage brokers trading girls to sex tourists. Rasmia was kept in a hotel room for two weeks before "her husband" went home.
"I felt insulted, scared," she said. "I had a nervous breakdown. My father went to the broker but we had no proof of the marriage. . . . All my neighbors knew I was a prostitute, all my friends abandoned me. My future is destroyed. Now three girls in my street have been Saudi wives."
The phenomenon is increasing in Cairo, says Mohammad Gazer, who has set up a charity to warn families. "It is becoming clearer and clearer to Saudi men and other tourists that Egypt is the place for child marriage, for ignoring girls' and women's rights. It has got worse since the revolution and keeps getting worse every day."