Final answer:
Sperm emission starts during puberty. The first ejaculation generally occurs around the age of 13. Sperm production continues throughout a man's life, but may decline in later adulthood.
Step-by-step explanation:
Sperm emission, or the release of sperm from the male body, starts during puberty. The first ejaculation generally occurs around the age of 13, although full fertility may not be gained until a year or two later. Sperm production continues throughout a man's life, but the number and quality of sperm may decline in later adulthood.