'There's a huge amount that we don't understand': Why sperm is still so mysterious

Sperm are tiny but incredibly important cells that carry the father's genetic material to the mother's egg during reproduction. A man produces about 1,000 sperm every second, and during intercourse, millions of sperm are released to compete in a race to fertilize a single egg. Despite their importance, many aspects of sperm biology remain mysterious even after centuries of study. Questions like how sperm swim, how they navigate the female reproductive tract, and what exactly they are made of are still being explored by scientists.

Recent advances in technology have allowed researchers to track sperm from their creation in the testes to their journey through the female body. These studies have revealed surprising details about sperm movement and the changes sperm undergo once inside the female reproductive system. Sperm are unique cells with specialized structures and functions that set them apart from other cells in the human body. They are the only cells that can survive outside the body for a time and must be flexible enough to travel through the female reproductive tract.

Sperm develop in the testicles starting at puberty, transforming from simple round cells into complex cells with a head and a tail. The tail, called a flagellum, propels the sperm forward. It takes about three months for sperm to mature. After ejaculation, sperm swim through the female reproductive tract, facing many challenges along the way. Only a few sperm make it to the egg, and only one fertilizes it. Scientists are still uncovering the details of how sperm swim and how they find and penetrate the egg, making this a fascinating area of ongoing research.