The way of thinking is, it would be easy for a man to sexually abuse a child sitting on his knee, even in full view of parents, but not possible for a woman to do the same thing.
Nurseries are now extra strict. The one my Granddaughter goes to two afternoons per week is like Fort Knox. No one gets in without buzzing and being recognised. My Daughter was standing with a lady last week and when she buzzed the staff let my Daughter in but refused the lady who was a child's Grannie, come to pick her up, they refused admission because they did not know her. They made her stand outside until they made a phone call to the child's Mother and even then they demanded I.D. Inside the Nursery are security cameras on the walls, but no mobile phones or cameras are allowed inside the place, even staff phones etc., The Christmas Photograher was checked out and had special permission to only take the Santa pictures. There is a list of rules and regulations as long as your arm.