A child of four may ask questions on this matter, simply and spontaneously.

As soon as the questions are put, certainly as soon as they become at all insistent, they should be answered, in the same simple and spontaneous spirit, truthfully, though according to the measure of the child's intelligence and his capacity and desire for knowledge.

This period should not, and, if these indications are followed, naturally would not, in any case, be delayed beyond the sixth year.

After that age even the most carefully guarded child is liable to contaminating communications from outside.

Moll points out that the sexual enlightenment of girls in its various stages ought to be always a little ahead of that of boys, and as the development of girls up to the pubertal age is more precocious than that of boys, this demand is reasonable.
If the elements of sexual education are to be imparted in early childhood, it is quite clear who ought to be the teacher.