I have the fear and fight it every day. The hardest thing is not to give in to panic thoughts or paranoia, nor over-compensate by not making judgments at all, but steer a middle course.
My DH is the at-home parent and faces the very blanket suspicions being discused on this thread. Maybe this is why the majority of other parents he has befriended and socialises with are European or Antipodean, not British? I don't know, but the British mothers in particular seem to both of us to be more prone to the paranoia reaction. It is very sad.
We all have to try anad make judgments of what risks are out there, and do as best we can. The kind of knee-jerk anti-men attitudes displayed on the other thread are the absolute antithesis of the thought process you need to make proper judgments. Children brought up by those kind of parents are, I think, prardoxically more at risk than children whose parents try to make assessments on a calm, case-by-case basis.