[The begetting of a boy or of a girl respectively]

The sex-ratio was established on the basis of the fertility index (F.I.), i.e. the total number of forwards motile and morphological normal spermatozoa in ejaculate. It was stated that the fecundation of a boy needed a higher F.I. The age of the father was not interesting. The F.I. was lower after hormonal treatment, this means: a higher fertilizing capacity on the basis of the treatment. This fact explains, why it is possible to fecundize with lower F.I.