For the past 20 years, Barbara Harris has been driving around the country in a branded RV, advertising her nonprofit to drug addicts and alcoholics. Her organization, Project Prevention, pays substance abusers $300 to get sterilized or put on long-term birth control like an implant or an IUD. To date, she has paid more than 7,000 people, mostly women, to basically give up their fertility.

Using cash incentives, she feels like she is stopping a societal problem in its tracks. “We’re preventing women who are strung out on drugs and alcohol from conceiving a child,” Harris says. “Nobody has a right to force-feed any child drugs and then deliver a child that may die or may have lifelong illnesses.”

It seems straightforward enough, but the ethical questions behind Harris’s program are not. VICE News caught up with Harris during her first road trip this summer, stopping where addicts or those who know them hang out and speaking to longtime critics who think Project Prevention may be contributing to the very problems Harris set out to solve two decades ago.