For many couples surrogacy can be their path to parenthood. But it can cost tens of thousands of dollars. A big business that some are now saying is wrong and maybe even downright dangerous. Here's... See More
For many couples surrogacy can be their path to parenthood. But it can cost tens of thousands of dollars. A big business that some are now saying is wrong and maybe even downright dangerous. Here's ABC's linsey Janis. Why can't you tell me how much money you were paid? This woman, Jennifer lull-s on a mission to put an end to surrogacy. Empowered women -- empowered women can say -- Empowered women can make their own choices. Reporter: Tracy Bullard is standing up for surrogate mothers everywhere. I take the position we shouldn't be doing this. Reporter: Jennifer lull is here in Minneapolis screening her latest documentary, "Breeders: A subclass of women," in which she argues that the surrogacy industry needs to be stopped. Women are not breeders. Children are not products and commodities. You know, women are not easy-bake ovens baking cupcakes for other people. Reporter: Her documentary features women who have deep regrets about becoming surrogates. The first time they picked up the baby and brought him over to my side and just held him up. I've never seen or heard from him since. I think about him every day. Reporter: Lahl is a mother of three, a former neonatal nurse, the president of the conservative-leaning center for bioethics and culture, and she holds a master's in bioethics from a well-known evangelical university. Some of your critics say that your views are based on your religious beliefs. Yeah. Because that's an easy card to play. Because then the people say, you know, she's this, she's that. But I tell people all the time, I'm against surrogacy. I don't care if you're gay, straight, single. Reporter: Lahl accuses the multibillion-dollar global industry of concealing the health risks for prospective surrogates and equates it to selling organs. If you want to be a kidney donor, we say that's wonderful. But you are not allowed to be paid. We say no. Because what happens when commerce enters in is people will make decisions that are not in their best interests for their health. Reporter: Lahl's anti-surrogacy position is quite controversial, especially since children born through gestational surrogacy is on the rise. In fact, surrogacy has had some high-profile attention, from Nicole kidman to Sarah Jessica parker and Ricky martin. All using the method to expand their families. A couple spend their entire lives wanting a child and not being able to have one just kind of resonated with me. Reporter: Tanya Prashad, a one-time surrogate mother, supports lahl's argument. Back in 2003 she was the surrogate for a same-sex couple using her own egg and regretted it instantly. And then when she was right there in my arms all those little pieces of paper that we signed just kind of fell away. I never thought about her. I never for a second thought about what was right for her and what she deserved. Did you feel guilty? Horrible guilt. And shame. Both. An even mix of both. You felt like someone who'd given their child away. I felt like someone that sold my child. Reporter: Even though she signed away Herr legal rights, Tanya worked out a deal with the child's parents that she'd still be involved. What was your understanding of the agreement? That I would have a baby and she'd live with them but I'd always be a part of her life. There's not another mom. So I would -- the plan was for me to still act in the capacity as her mom. Reporter: But she says that's not what ended up happening and over the years Tanya fought to keep a relationship with the daughter she gave birth to. So then we ended up in court and we actually agreed on a joint custody order together. Reporter: But lahl believes it's not just the mothers. She says the newborns suffer too. The fracture of that bond can have significant damage. Short-term and long-term. Is there any actual evidence that it's harmful to the child? There's a study that just came out last year, and that study actually showed that these children around the age of 7 had some behavioral, some developmental problems. These are people's lives that are being formed now and we're going to ask to study it after the fact? Shouldn't we stop and really look at what we're doing and say what is in the best interest of children? Reporter: That study she's referring to is by researchers at Cambridge university and it showed higher levels of psychological problems for surrogate children at age 7 then the comparison group of naturally conceived children. However, those children showed above average psychological well-being. And the study showed differences disappeared by age 10. I think we have to be careful in interpreting this data and laterally not throw the baby out with the bathwater so to speak. Reporter: Dr. Jen Ashton says we're really just beginning to understand the impact of surrogacy. I think the people who have concerned about it really need to reserve judgment till a lot more long-term data is known. Reporter: But Tanya believes her 10-year-old daughter is still overcoming issues stemming from being born this way. She's got a lot of insecurities and a lot of fear. She needs a lot more reassurance. She needs that extra pat, that extra hug, that extra everything's going to be okay. Reporter: That Cambridge study also tells us that there are likely raised levels of psychological problems for surrogate children at age 7 because that's when they gain a better understanding of how they were born. And they have questions. I'm a product of a traditional surrogacy. Reporter: Like Jessica kern, who says she spent her entire childhood in the dark, wondering why she looked so different from the woman who was raising her. Eventually discovering her biological mother was the surrogate and went about tracking her down. I know exactly how much she earned for delivering me. How much was it? $10,000. You believe she was motivated by money. You can't say that's not motivating. I think one of the most important things for people to remember when they talk about unconventional ways to become parents today is a lot more goes into being a parent than biology. It's very important to remember that. Because people can get very, very emotional when they talk about these types of issues. The medical ones are straightforward. The social ones get a little trickier. Empowered women can say -- Empowered women can make their own choices. Reporter: But even with all the evidence lahl cites, she's still got her critics. Why can't you tell us how much money you were paid? Are you not sympathetic to couples who are infertile or to same-sex couples that cannot have their own biological children? I'm incredibly sympathetic. But just because somebody can't have a child doesn't mean that I have to say by all means, any way you can get the child is fine. There's a long step between I can't have a child and what are the ethical ways to fulfilling that need to getting a child? Reporter: For "Nightline" I'm Linzie Janis in Minneapolis, Minnesota.
This transcript has been automatically generated and may not be 100% accurate.