What are chemical messengers that control the development and function of the reproductive system known as?

Chemical messengers that control the development and function of the reproductive system are known as sex hormones. These hormones, which include estrogen, progesterone, and testosterone, play crucial roles in various biological processes related to reproduction, including sexual differentiation, the menstrual cycle, and the development of secondary sexual characteristics. They are produced primarily by the gonads (ovaries and testes) and can influence many target tissues throughout the body, thereby regulating both physical and emotional aspects of reproductive health.

The other options do not fit the definition as precisely. Enzymes are biological catalysts that facilitate chemical reactions, but they do not act as messengers. Neurotransmitters are chemicals that transmit signals across synapses in the nervous system, playing roles in communication between nerve cells rather than directly regulating the reproductive system. Cytokines are signaling proteins involved in immune responses and cell communication, not specifically tied to reproductive processes. Hence, sex hormones are the key chemical messengers that directly influence the functions of reproductive systems.