determine due to menarche. While there is variation in the onset time and magnitude, the sequence of events stays more or less consistent, variations in the sequence can indication a pathological condition. Dietary influence Differences in quality and quantity of nutrition account for one of the strongest environmental factors that alter the onset of puberty. Evidence has linked childhood obesity in girls with early pubertal timing, referencing an increased amount of body fat as a signal for the brain to initiate puberty and due to an excess of available energetic resources, since developing a fetus is very energetically demanding. Illness Disease and chronic illness in childhood can lead to a delay in pubertal timing in boys and girls. Inflammatory diseases, parasitic infections, and other illnesses that affect nutritional intake, specially chronic ones, are energetically costly and energy and resources has to be allocated into maintenance and health, sometimes taking energy from growth or reproduction, stunting or delaying them. Genetics and environmental causes Variation in pubertal timing has been directly found to be due through direct genetic association between mothers and daughters in 46% of the population studied. It is believed that an androgen receptor gene, but the specific gene has not been found. Chemicals and hormones found in the environment and plastics such as Bisphenol A (BPA) have been thought to affect sexual development in humans at the prenatal or postnatal stage. According to the Centers for Disease Control and Prevention (CDC), BPA found in plastic bottles and containers leaches into foods and liquids when warmed up, as in the case of plastic baby bottles, and traces of the chemical were found in more than 90% of the U.S. population studied. BPA is of concern because it interferes with the actions of estrogen which is needed as a developmental and reproductive regulator. Stress and psychosocial factors Most of the studies have reported that menarche may occur a few months earlier in girls in high-stress households, whose fathers are absent during their early childhood, who have a stepfather in the home, who are subjected to prolonged sexual abuse in childhood, or who are adopted from a developing country at a young age. Conversely, menarche may be slightly later when a girl grows up in a large family with a biological father present. However, when the stress is severely high and potentially life-threatening such as in times of war, the onset of