As a non-chemist I don't claim to have a comprehensive understanding, but as far as I can tell: PTFE (Teflon) is found in consumer products today, and has not been directly linked to cancer yet, i.e if you eat teflon (and you have) it will supposedly just pass through your gut in an inert fashion. PFOA and more generally PFAS are used to manufacture PTFE, these are known carcinogens according to independent studies and (allegedly) internally by 3Ms own research, unfortunately PFOA is also in your blood and my blood, not because you ate teflon from a frying pan, but because once it's in the environment it doesn't get broken down, and so inevitably we end up ingesting it.
The reason we have to generalise to the group of chemicals "PFAS", is because once PFOA specifically was found to be problematic companies looked for similar alternatives, but these have also found to cause similar issues.
To complicate matters the PTFE in your non-stick frying pan can also releases PFOA if heated high enough, supposedly the threshold is around 300 degrees C, however it has been found that this threshold varies between products and can be realistically reached under in "normal" cooking scenarios, but usually when someone accidentally dry heated a frying pan too much, or is just plain cooking on too high a temperature. The side effects of being exposed to PFOA in this way are supposed to feel similar to catching a cold that disappears fairly quickly, and is often mistaken as such, I presume this is because it's vaporised.
Even knowing all this (that provided you don't nuke your cookware it likely makes no personal difference) I've still decided to personally go down the stainless steel route, it's not very scientific, but the relationship between PTFE and PFOAs is close enough, and it flakes off my frying pans frequently enough that I've decided I don't want to keep on ingesting it only to find out later that it's also a problem. Although stainless is not hazard free, because you can get problems with metals leaching into the food and have to be careful with acidity, and also make sure you buy high quality pans. They also require more skill to cook with without destroying them, but ultimately last indefinitely if you can take care of them.
The main problem with continuing to use PTFE in products is the indirect cost to the environment and human health through the "externalities" of manufacturing.
