(CNN) -- Child slavery has escalated six months after a devastating earthquake demolished the Haitian capital and left a generation of orphans, according to an advocate who works in the Caribbean nation.
Jean-Robert Cadet is the author of "Restavek," a book on the plight of Haiti's child slaves. The word, derived from a French expression that means "'stay with," refers to children given by a biological parent to a family for the purpose of doing minor housework in exchange for school, food and housing.
"Once children enter the family, they become a domestic slave and they are at the mercy of everyone in the house," Cadet said. "The only thing worse is if the child is a girl, because there is sexual abuse and the risk of pregnancy once she reaches puberty."
If a girl gets pregnant, she is ousted from the house and sent to the countryside.
"About 80 percent of the slaves are girls and they are so vulnerable," according to Cadet.
Cadet is headed to Haiti on Monday to visit some of the tent camps and monitor treatment of restavek children.
The plight and the number of restavek children have increased after the January 12 earthquake, he said.
"Usually, in times of crisis, restavek children will receive very little food and are exposed to harsher elements than other Haitians," he said.
The author said his plan is to ensure camp directors, who are paid to create social programs, are helping children deal with the trauma of the earthquake. Most of the social programs are financed by nongovernmental organizations, such as Red Cross and the United Nations Children's Fund.
The earthquake last year killed more than 300,000 people, according to the Haitian government, and left almost an entire generation of children homeless and orphaned.
"It's these children who will be absorbed into restavek," Cadet said. "Before the earthquake, UNICEF had estimated about 300,000 children were in domestic slavery. I suspect the number will double unless the international community does something drastic, such as push Haiti toward universal education to make sure every child is in school."
Cadet said he visited some tent camps and witnessed people who offered their neighbor's children to be domestic slaves.
"I was able to get three of the children and two have come to the U.S." he said.
Cadet's passion to rescue children from slavery comes from personal experience. His says his mother died when he was 4, and he was given as a restavek to a Haitian family in the capital, Port-au-Prince.
By the early 1970s, the family moved to the United States in search of a better life.
"Today I have a foundation that tries to put an end to the restavek system and to advocate the demise of child slavery," he said.