In 2001, when Kimberly Wypychowski adopted her son, Ruslan, from Ukraine, he was 5 years old and she wanted to give him everything. She bought him fancy clothes, new toys, even a motorized tractor to drive around their Phoenix, Ariz., neighborhood. There was one thing, though, that Wypychowski couldn't provide. "I knew one day he'd ask me why his father left him at an orphanage," she says, "and I wouldn't have the answer." So she hired Anna Sternad, a "searcher," who helps track down birth families overseas. Five weeks later, Wypychowski received baby pictures of her son and a letter from his biological father. It was earth-shattering, she says.

For Sternad, and the handful of other searchers like her who find out what they can about birth families abroad, it's all in a day's work. "It's satisfying," says Sternad, who's worked for 250 adoptive families in the past three years, "to give these children a way to figure out who they really are."

In the past decade, about 170,000 families in the United States have adopted children from China, Eastern Europe, Central America and India. Most don't push for more information, but a growing number are eager to find out more about their child's past. So they're hiring searchers--English-speaking agents who work with teachers, translators and private investigators in the child's home country. For $600 to $5,000, the searchers, who advertise on the Web, scour public records and welfare rolls and interview adoption officials, police officers and orphanage administrators. Sometimes they go door to door.

Fifteen years ago, relationships between adoptive parents and birth families overseas were almost unheard-of. Back then, parents who adopted domestically were encouraged to have some contact with birthmothers. Couples who believed that less contact was better for their family often opted to adopt internationally. Children needed homes, and "the distance ensured that birth parents could never interfere," says Karen Holt, who runs a Web site for adoptive parents. These days, more adoptive parents want whatever scraps of information they can get, from medical history to details about their child's ancestors and siblings--and some say they launched their search at the request of the children themselves. The kids "don't want to go back," says Mary Kirkpatrick, a searcher from Phoenix who helps find families in Russia. "Sometimes they just want to know what they came from."

In some countries, though, those details are impossible to come by. In China, most children put up for adoption are abandoned. So Adele Hall, a searcher from San Antonio, Texas, uses her network in China to find police reports or "anything that might provide details of the abandonment." Happy endings aren't the rule: Hall's greatest success has been to connect adoptive parents with the person who first found their baby. In other countries, where mothers can be found, sometimes they can't or won't acknowledge parenthood.

Last month the Wypychowskis traveled to Ukraine for a face-to-face visit with Ruslan's birth family. They got a warm welcome--and Ruslan got to play with his biological brother. But there were awkward moments, too. "To them, we seem like millionaires," says Kimberly, "and sometimes they begged for money." But the Wypychowskis learned to look past it. Because with family, that's what you do.