I still made sassafras tea even though the surgeon general said it was a carcinogen. I guess if I was fed it like they do the rats in labs possibly might cause harm but I think you would have to eat a whole lot of pawpaws to do any kind of harm. The leaves from them are pretty good insect repellent.I was planning on putting some of these in, then found some info about them having a neurotoxin, annonacin. It seems to possibly only be an issue with long-term consumption, but ultimately not a risk I wanted to take. YMMV.
American pawpaw
Asimina triloba, commonly known as pawpaw, is native to North America and has edible bean-shaped fruits. The plant extract is used in anti-lice shampoo and in pesticides. In the lab, pawpaw appears to be toxic to some cancer cells, but such effects have not been shown in humans.www.mskcc.org