- A healthy man releases about 1–2 teaspoons of semen per ejaculation, containing approximately 15–200 million sperm, but only one (or rarely a few) can fertilize an egg.
- The average speed of ejaculation is about 45 km/h (28 mph), propelled by strong muscle contractions.
- The human egg (ovum) is the largest cell in the body, about 0.1–0.2 mm in diameter, visible to the naked eye, while the sperm is the smallest, at about 0.05 mm long.
- Sperm can survive in the female reproductive tract for up to 5–7 days, waiting for an egg to fertilize.
- The clitoris has over 10,000 nerve endings, making it one of the most sensitive parts of the human body.
- During pregnancy, the uterus expands up to 500 times its normal size to accommodate the growing fetus.
- The placenta, a temporary organ, forms during pregnancy to supply nutrients and oxygen to the fetus and is expelled after birth.
- The female ovaries contain about 500,000 egg cells at birth, but only about 400 will mature and be released during a woman’s lifetime.
- The shortest recorded human pregnancy resulting in a healthy baby was 21 weeks and 1 day.
- Testicles are kept outside the body in the scrotum to maintain a temperature 2–3°C cooler than the body, optimal for sperm production.
- The female reproductive system can influence sperm selection through biochemical mechanisms in the cervical mucus, potentially favoring certain sperm.
- The first known contraceptive, used by ancient Egyptians around 2000 B.C., was a mixture including crocodile dung, though modern methods are far more effective!
- Average vaginal depth is 3–6 inches, but it can elongate during arousal to accommodate penetration.
- Men produce sperm continuously from puberty, but sperm quality and quantity can decline with age, influenced by lifestyle factors like smoking or obesity.
- Every human begins as a single cell (zygote), formed by the fusion of sperm and egg, which divides to form an embryo within hours.
- There are approximately 5 calories in a teaspoon of semen, mostly from sugars and proteins.