The reproductive cell are called gametes:

• The female egg cells (óvulos). Ovaries produce an egg cell every 28 days.

• The male sperm cells (espermatozoides). Testicles produce millions of sperm cells every day.

Male and female bodies are different. These differences are called sex characteristics:

• Primary sex characteristics are the differences between the reproductive organs. They exist from birth.

• Secondary sex characteristics are male and female differences that appear during puberty.