IGCSE Biology glossary
Testis
Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
Definition
The male reproductive organ that produces sperm cells and secretes the hormone testosterone. The testes are located outside the body in the scrotum, where the temperature is slightly lower than body temperature, which is necessary for sperm production.
What to include in an exam answer
The plural is testes. Testosterone triggers male puberty changes (voice deepening, muscle growth, facial hair). Know that testes are outside the body because sperm production requires a lower temperature.
Example in context
Explain why the testes are located outside the body (2 marks): Sperm production requires a temperature slightly lower than body temperature. The scrotum holds the testes outside the body cavity where the temperature is cooler.
Related syllabus topic
Reproduction