What organ is responsible for producing gametes?

The gonads are the organs specifically responsible for producing gametes, which are the reproductive cells necessary for sexual reproduction. In males, the gonads are the testes, which produce sperm cells, and in females, the gonads are the ovaries, which produce egg cells (ova). This function is crucial for sexual reproduction, as the fusion of male and female gametes leads to the formation of a zygote, eventually developing into a new organism.

Other organs listed, such as the adrenal gland and the thyroid gland, have roles related to hormone production and metabolism regulation, but they do not produce gametes. The pineal gland primarily secretes melatonin and is involved in regulating sleep-wake cycles rather than reproductive functions. Therefore, the gonads are uniquely positioned to facilitate reproduction through gamete production, making them the correct answer.