Worldwide, the incidence of infertility is about 10% to 12%. Infertility can be primary, in which conception has never occurred, or secondary, in which there has been an inability to conceive after having carried at least one pregnancy to term. This chapter covers major medical and sexual causes of infertility and its treatment, and how these affect contemporary couples in their quest to become parents. Infertility counseling is a mental health niche in its own right; the focus here is on diagnosing and treating the sex and intimacy issues that may undermine a couple’s efforts to conceive. The medical causes of infertility described are: sexually transmitted infections, lifestyle factors, decline in ovarian reserve, polycystic ovarian syndrome, amenorrhea, menopause, endometriosis, pelvic inflammatory disease, cancer and its treatment, genetic etiology, obstructive etiology, and systemic disease. The sexual causes described are vaginismus, erectile dysfunction, premature ejaculation, and delayed and retrograde ejaculation.