Male Reproductive System Testes: Produce sperm and testosterone. Spermatogenesis: Formation of sperm occurs in seminiferous tubules; sperm matures in the epididymis. Hormonal Control: Testosterone influences secondary sexual characteristics and spermatogenesis, regulated by FSH and LH via negative feedback. Female Reproductive System Ovaries: Produce eggs and female hormones. Oocytes are present at birth and mature monthly during reproductive years. Menstrual Cycle: Includes four phases (flow, follicular, ovulatory, luteal), regulated by FSH, LH, estrogen, and progesterone. Hormonal Control: Estrogen and progesterone regulate ovulation and endometrial preparation for implantation. Fertilization and Pregnancy Fertilization: Occurs in the fallopian tubes; a zygote undergoes divisions (morula, blastocyst) and implants in the uterus. Embryonic Development: Progresses through gastrulation (formation of ectoderm, mesoderm, endoderm) and morphogenesis. Placenta: Facilitates nutrient and gas exchange; produces hormones to sustain pregnancy. Birth and Lactation Birth: Triggered by hormonal changes (increased oxytocin, decreased progesterone), leading to uterine contractions and delivery. Lactation: Initiated by prolactin and oxytocin; provides nutrients and antibodies through breast milk. Contraception Methods Includes abstinence, hormonal pills, IUDs, and sterilization, with varying effectiveness and side effects. Assisted Reproductive Technologies In Vitro Fertilization: Fertilization occurs outside the body; embryos can be frozen for future use. Artificial Insemination: Sperm is directly introduced into the female reproductive tract. Sexually Transmitted Infections (STIs) Examples include HIV/AIDS, chlamydia, gonorrhea, and syphilis. Prevention methods: monogamy, proper condom use, and regular medical checkups.