PIP: The Eugenics Society's 23rd annual symposium was held in Septamber, 1986 on Natural Human Fertility: Social and Biological Mechanisms. Opening the symposium, Dr. Malcolm Potts stressed the scale of the problem that fertility poses for the human species, with 1 million individuals being added to the world population every 4 days. Any insights into what nature gave us by way of capacity for controlling fertility are greatly needed, and the theme of the symposium is 1 of importance and urgency. Topics that were discussed in various papers given at the symposium include: 1) natural fertility in man and animals, 2) physiological and behavioral factors of fertility, 3) the male contribution to fertility, and 4) fertility and pathology.