I'm not confidently clinging, just saying there's a probable causality link. My father has several brothers and sisters, none got Parkinson's but none worked w

I'm not confidently clinging, just saying there's a probable causality link. My father has several brothers and sisters, none got Parkinson's but none worked with herbicides. An acquaintance that was also an agricultural engineer, colleague of my father, also got Parkinson's. There were lots of people in the town around those chemicals but noone kept track. They're almost all gone by now, but old age is also a factor. On the other hand it's almost certain not all got Parkinson's so funk knows. Again I didn't verify and I'm not in the mood to verify, although it would be possible since it's a small town. Go round every house and ask if their deceased relative had Parkinson's. But to what purpose?