Based on this, he proposed five universal stages of development, that each is characterized by the erogenous zone that is the source of the child's psychosexual energy. The first is the "oral stage", which occurs from birth to 12 months of age. During the oral stage, "the libido is centered in a baby's mouth." The baby is able to suck. The second is the "anal stage", from one to three years of age. During the anal stage, the child defecates from the anus and is often fascinated with their defecation. The third is the "phallic stage", which occurs from three to five years of age (most of a person's personality forms by this age). During the phallic stage, the child is aware of their sexual organs. The fourth is the "latency stage", which occurs from age five until puberty. During the latency stage, the child's sexual interests are repressed. Stage five is the "genital stage", which takes place from puberty until adulthood. During the genital stage, puberty starts happening.