Introduction

It is commonly asserted that new technologies drive political, social and ethical changes. However, such influences are rarely unidirectional (Theodosiou and Johnson, 2011); indeed, historically the technologies and practices of sperm donation were themselves much influenced by social, ethical and political considerations. However, the advent of in vitro fertilization technology undoubtedly provided a powerful stimulus to sperm, embryo and egg donation, and the nature of many of the ethico-socio-political issues generated were themselves resolved or changed by the further refinements of single sperm injection, and the capacity to freeze and store gametes and embryos. Whether these technologies can or should be applied or not, and if so how, is of course much influenced by socio-ethical factors. This chapter examines some of the basic medico-scientific issues as a background to the complex and bidirectional interactions with ethics that follow.

Infertility and sterility

Fecundity is a measure of reproductive potential, and where that potential is zero, the individual (or couple, or population) is said to be sterile. In contrast, fertility is a measure of reproductive outcome and is usually expressed in terms of children born per woman, per couple or per population unit. Infertility is a measure of the failure to produce children, and is variously defined as occurring after a specified period of time – for example one or two years of attempts. Infertility may result from sterility but not necessarily so; a sole individual or two of the same sex will be infertile however long they try for children, but need not be sterile. This distinction has led to the concepts of medical and social infertility, and both are the subjects of this volume.