ABSTRACT
THE ZUCKERMAN THEORY One of the definingmoments in the history of reproductive biologywas in 1950 at the Laurentian Hormone Conference held in Franconia, New Hampshire. Probably the audience, and possibly even the keynote speaker, did not realize that a foundation stone was being laid, which would profoundly affect the course of scientific endeavor. Solly Zuckerman, a British primatologist from the University of Birmingham (Fig. 1A), presented a paper with a deceptively simple title, “The number of oocytes in the mature ovary,” which appeared in print the following year (1). He argued, contrary to the popular view of his time, that mammalian oocytes are only formed before birth and cannot be replenished afterward, a theory that has held sway ever since and has only recently received its first serious challenge. His theory posits that the early fixing of the oocyte population sets an upper limit on the potential number of ovulations and the length of the reproductive life span and hence has become central to our understanding of the biology of menopause. Moreover, the longevity of oocytes in the late reproductive years provides a plausible explanation for the dramatic effects of ageing on oocyte quality, at least in human ovaries, namely, accumulated effects of reactive oxygen species and other harmful factors. Thus, the Zuckerman theory has had tremendous explanatory power for ovarian physiology as well as being a major influence in human and animal medicine.
