The anterior region of the hypothalamus then alters the activity of the neuroendocrine system which is involved in reproductive physiology and behavior. Some nerve fibers may also be linked to the limbic system, which is involved in emotions. The most likely answer is our apocrine glands. The three types of glands that are present in humans are sebaceous glands, sweat glands and apocrine glands. Sebaceous glands exist around the body's openings and secrete substances that kill potentially dangerous microorganisms.
Sweat glands help regulate our body temperature and release water and salt.
Apocrine glands in humans do not regulate body temperature as they do in other animals. They are found in large concentrations on the face, chest and wherever body hair exists. Interestingly, apocrine glands become functional after puberty which is when we would most likely be searching for a mate. More evidence for the existence of pheromones comes from research that was done almost thirty years ago and a carefully controlled experiment that was just recently published. The experiment was based on the research that showed that women living in close proximity to one another often found that their menstrual cycles would converge over a period of time.