In humans, the pineal gland controls our biorhythms and works in conjunction with the hypothalamus gland to control our thirst, hunger, sexual desire and biological clock that is associated with the aging process.he high melatonin levels in children are believed to inhibit their sexual development until melatonin levels decrease when puberty begins. Melatonin is created when the amino acid tryptophan is converted into the neurotransmitter serotonin, which is in turn synthesized into melatonin.