Sexuality, Reproduction, and Birth

Abstract

The chapter extends discussion of the human reproductive life course by providing a focus on male and female sexuality and the common result of that sexuality, the production of offspring via childbirth. It begins with an overview of sexuality in non-human primates, with emphasis on variability, considering ways in which sexual behaviours of our closest relatives are both different and similar to sexual behaviours of humans. The chapter addresses sperm competition, male and female orgasmic response, and homosexuality. The approach includes both evolutionary medicine and evolutionary psychology. The chapter considers the hours that surround the production of offspring, beginning with labour and delivery and concluding with the early postpartum treatment of the new-born infant. Topics covered include the role of the hormone oxytocin, the stages and phases of labour, posture in labour and delivery, surgical delivery, postpartum haemorrhage, neonatal hyperbilirubinaemia, treatment of the new-born, mother–infant bonding, postpartum depression, and breastfeeding. Although there are aspects of labour and delivery that benefit from clinical assistance and consideration by evolutionary medicine, most of the time the process progresses with little or no intervention as it has for thousands of generations.