Adoption can be a beautiful thing. Bringing together babies who need parents with parents who are desperate for children. Ab childrere adopted into new families by american parents every year. I was... See More
Adoption can be a beautiful thing. Bringing together babies who need parents with parents who are desperate for children. Ab childrere adopted into new families by american parents every year. I was once one of them. But now comes a highly unusual new way to make a match. Craigslist. That's right. A place where people buy and sell their old stuff, that marketplace is now facilitating adoptions. Good idea? We asked abc's reena ninan to take a look. Reporter: What you're about to see is a most unusual family reunion. Hi! Reporter:2-year-old ben welcoming his biological mother into his home for the very first time. His adopted family right behind him. Hi! ReporTRAORDINARY Journey for all of them. Tammy, the girl from the wrong side of the tracks, who gave ben up. Tracy, the suburban mom who took him in. Perhaps most stunning, though, is how they found each other. What do you say when you tell people, I found my baby on craigslist? Yeah, well, I try to phrase it a little differently, but people do sort of give us a look. Like, on craigslist? Reporter: Yes, on craigslist. The world's most famous online marketplace. The site where you can find anything. Even a child these days. Adoptive parents across the country are taking the controversial step of connecting direct it will with potential birth mothers. All with just the click of a button. Craigslist put the power back in parents and birth moms hands. Reporter: Yahoo! Reporter piper weiss has been investigating the world of private adoption online. But it also forces both of them to be their own filter and to be kind of their own expert in the matter and that takes a lot of -- there's a lot of risk and reward to that. Reporter: Megan and steve in buffalo new york learned it the hard way. After successfully adopting aiden, they wanted to give him a brother or a sister. So, they started advertising online. They were contacted by a woman claiming to be pregnant. I thought it was -- it was a little bit sketchy, because we'd get a new phone call and it would be like, you know what, we really need that $50 for gas and by the way, I'm going to need that weekly. When somebody is pushing money, money, I need yesterday, it's instabtly a concern. Reporter: Megan and steve's adoption coordinator googled the woman's name, kimberly, only to discover she had been convicted of sending bad checks, identity theft and burglary. Report Do you get discouraged? All the time. There's great days and then there's not great days. And the thing that keeps you going is knowing that it had to happen. And it will. Reporter: Tracy and dan had the same optimism during their search for a child. They tried everything. They designed their own website. Even plastered their car with this ad. You don't wait for a job, you look for a job. Why would you wait for a baby? Reporter: After spending so much time, energy and money, nothing seemed to work. They decided to try something different. Did you think it's a little crazy, though? I'm going to search for our future baby online on craigslist. Well, we met online. So, if I were going to look up a word in the dictionary, i wouldn't go to my bookshelf and open up my dictionary. You just turn to the internet. The second I read their ad, i called there. Hi, I'm pregnant. And I need help and she was like, we're really happy you called. Reporter: Tammy nelson was stuck in a nightmare. Financially dependent on her abusive husband and already raising one son, rider. I remember one time, feeding my son the dust out of the rice krispie box. The last bowl of cereal w had and I didn't know where the next meal was going to come from. Reporter: But her nightmare got worse when she says her husband forced her to get pregnant again. You hate yourself a lot for it, because you feel like you should just have a connection with something that's naturally inside you. I felt guilty that I never had that connection. Reporter: For tammy, abortion wasn't an option. Giving up the child was the right and only thing to do. What do you think? Ten fingers, ten toes. Reporter: What was it like the first time you went and saw ben? She wanted me in the room while he was born, so, they put him right in my arms, so -- Reporter: What was that like? Amazing. Reporter: Two years have passed. Tammy started rebuilding her life with a new partner, now fiance patrick. Boom! Reporter: She's been watching ben grow up through facebook updates. It is hard seeing ben be able to do stuff that I was never able to afford for my first Reporter: Like what? Like gymnastics. I think every parent wants the best that they can do for their kid. I'm happy that ben has it, but it also kind of shows my inadequacies with my own son. Reporter: There's been very little direct contact. She's seen ben only once since he was born. He's so young. He doesn't really know what's going on. Just kind of an awkward situation, I guess, for everybody. Reporter: This past week, tracy and dan invited tammy over for a long anticipated visit to their home. Is that theirs? This is the house. Oh, my gosh. Hi! Reporter: The reunion is awkward. Ben is more interested in our cameras than his birth mom. Hey, ben. That. You like the right? Reporter: But the awkwardness pales in comparison to the overwhelming feeling tracy and tammy both have. Gratitude.Just can't thank you enough for everything. Everything. Such a great experience and he is so fantastic. You're everything I expected in a mom for ben and -- thank you. Reporter: I'm reena ninan for "nightline" in minneapolis. And our thanks to reena ninan. A special thanks, too, to yahoo! Shine who partnered with us on this report.
This transcript has been automatically generated and may not be 100% accurate.