Firefighters are at a higher risk of infertility than those who work in other professions. The scene of a fire may expose a person to a multitude of different chemicals, both in the burn and in the fire-suppressing foams (which typically contain PFAS). Exposure to PFAS is associated with decreased semen quality and reduced testosterone levels.
In addition, firefighters are at risk of increased scrotal temperature, either by being directly affected by the heat from fires or by heavy protective gear. Prolonged, increased heat around the scrotum can affect sperm production for months afterward.