Understanding male fertility Male fertility is the capacity to contribute sperm that can fertilize an egg and support the earliest steps of embryo development. Biologically, this requires coordinated function of the hypothalamus-pituitary-testes axis, the testes, epididymides, vas deferens, accessory glands,…

The male reproductive tract as a delivery network The male reproductive tract is designed to produce sperm, mature and store them, move them efficiently, and deliver them in a fluid medium during ejaculation. Its major components include the testes, epididymides,…

Where sperm production begins Sperm production begins in the testes, specifically within tightly coiled structures called seminiferous tubules. These tubules contain developing germ cells arranged in a highly ordered pattern, supported by Sertoli cells. Sertoli cells provide nutrition, structural support,…

What hormonal medications are designed to do Hormonal medications include drugs that supply, block, or modulate endogenous hormones such as estrogen, progesterone, and related endocrine signals. In menopause care, they are often used to reduce vasomotor symptoms such as hot…

What the research can and cannot tell us Fertility research often uses the term fecundability, meaning the probability of conception in a single menstrual cycle among people having intercourse without contraception. This is different from infertility, which is usually defined…

How medications can affect fertility Fertility is not controlled by a single organ or one laboratory value. It depends on coordinated hormone signaling, healthy gamete production, sexual function, and timing. Medications can disrupt any of these steps. In the male…

How cortisol fits into reproductive endocrinology Cortisol is produced by the adrenal cortex under control of the hypothalamic-pituitary-adrenal (HPA) axis. In parallel, reproductive function depends on the hypothalamic-pituitary-gonadal (HPG) axis, which regulates gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), follicle-stimulating hormone…

How chronic stress affects the reproductive axis Ovulation depends on coordinated signaling across the hypothalamic-pituitary-ovarian (HPO) axis. In a typical cycle, the hypothalamus releases gonadotropin-releasing hormone, or GnRH, in a pulsatile pattern. That pulse pattern tells the pituitary to release…

What stress-related infertility means In everyday language, people often use the phrase stress-related infertility to mean that anxiety, chronic pressure, or emotional strain seem to be interfering with conception. Medically, this is better understood as a situation in which stress…

How infections can affect fertility Fertility depends on a finely coordinated pathway: ovulation, egg pickup by the fallopian tube, fertilization, embryo transport, and implantation. An untreated infection can interfere with any of these steps, but the most established pathway is…