Becoming Female and Male: Our Extraordinary and Perilous Journey focuses on critical aspects in the development and biology of our reproductive system. A wealth of information not readily available to the general reader is complemented with a rich assortment of historical perspectives and commentaries. It begins with the amazingly complex, seemingly miraculous processed that lead to the formation of eggs and sperm, follows the fetal development of the genital tissues, the post-pubertal reproductive functions of females and males, the pubertal transition, and finally our reproductive twilight. The next section focuses on fertilization and implantation, birth and lactation, and exciting new studies relating the origins of chronic adult diseases to our pre-birth environment in the womb. The third section covers pregnancy loss and birth defects, while the final section reviews birth control methods, the causes of infertility and the new growth industry – assisted reproduction. In addition, three appendices supplement the main text and provide more detailed information about sex chromosomes, mutations, hormonal integrations of the reproductive system, and disorders of sexual development.