Reproduction is a fundamental problem for all organisms. Animal species exhibit a dazzling array of strategies to produce offspring, which often require large inputs of energy and are associated with major risks to their survival. Among mammals, females incur more direct costs of reproduction insofar as they carry (literally) the burden of embryonic and fetal growth and nourishment of the young through lactation. Thus the health of a female mammal directly affects reproductive outcome, both in terms of her fertility and the survival or death of her offspring. Human females experience these costs as a function of their mammalian heritage, but the variety of environments they inhabit generates substantial differences in the reproductive risks that women face. Their abilities to reduce these risks are important determinants of individual and population differences in maternal and child health and survival.

Given the centrality of reproduction to the lives of organisms, including humans, it is useful to know what constitute the optimal conditions for reproduction. Certainly, adequate nutrition, absence of infection, monitoring, and judicious intervention are among the factors that enhance pregnancy outcome. In biomedicine, complex technologies are routinely used to increase the odds of conception and a healthy newborn. In-vitro fertilization, fetal genetic screening, and cesarean sections are now routine procedures, and ever more complicated procedures such as fetal surgery are on the horizon.