How Sperm Are Made and Mature

Sperm production, or spermatogenesis, happens in the testes.
Each sperm takes about 70–90 days to fully mature.
The process begins with stem cells dividing into specialized sperm cells.
Testosterone drives the entire sperm-making cycle.
Mature sperm are stored in the epididymis until ejaculation.
Every day, millions of new sperm are created.
Only 1 in 200 million sperm typically fertilizes an egg.
Heat, stress, or toxins can lower sperm count and mobility.
The body continuously refreshes sperm supply throughout life.
Healthy sperm are essential for successful conception.