Pesticide Danger During Pregnancy

I live right next to a farm and I constantly think about pesticides this time of year. I do think they can cause problems, but I don't really know what. One doctor told me to get a reverse osmosis system and not let the kids outside when the fields are being sprayed. I don't know. My kids are fine so far. I don't have any reason to believe they were harmed because we live next to a farm. What do you think about pesticide exposure?