PON gene mutations
The PON gene is a gene responsible for the detoxification of organophosphorus and nerve gases in the liver. Many organophosphates (pesticides and insecticides) such as parathion, diazinon, and chlorpyrifos are known to be both carcinogenic, linked to birth defects or decreased fertility, they are also toxic to the brain and nervous system.
Newborn babies have very low levels of PON1, the enzyme that breaks down organophosphates, so it’s easy to see how a couple who have exposure to organophosphates can have trouble conceiving and even miscarry.
If you have mutations in PON (as per the below homozygous image), your chances of having toxic levels of pesticide or insecticide goes up, this contributes directly to infertility and or miscarriage.