Which glands are primarily associated with reproduction?

The glands primarily associated with reproduction are the gonads. In both males and females, gonads play a crucial role in producing the sex hormones that regulate reproductive functions. In males, the testes produce testosterone, which is essential for the development of male reproductive tissue and secondary sexual characteristics. In females, the ovaries produce estrogen and progesterone, which regulate the menstrual cycle, ovulation, and pregnancy.

The adrenal glands, while they do produce some sex hormones, are mainly responsible for stress response and metabolism, rather than direct involvement in reproductive processes. The thyroid glands are primarily involved in regulating metabolism, growth, and development, rather than reproductive functions. The pineal glands primarily secrete melatonin, which affects sleep patterns and circadian rhythms, and have no direct role in reproduction. Thus, the gonads are specifically designated for reproductive functions, making them the correct answer.