ABSTRACT
Human reproductive ecology has traditionally focused on variation i n female reproductive function i n response to such factors as caloric intake, activity, and psychological stress (for review see Ellison 1994). Research on individual and interpopulation physiological variation, coupled w i t h new hypotheses addressing the evolutionary significance of ovarian adaptabil ity, has enhanced our understanding of the mechanisms and constraints which underlie important demographic and life history variables. How ever, our understanding of the range and evolutionary significance of male reproductive adaptability is less clear. Nonetheless, new studies and theoretical developments are guiding present research and providing clar i ty to clinical and anthropological data.
