People stop growing taller when puberty is completed and the growth plates fuse together. Boys usually finish growing by age 16, while girls finish growing at age 14 or 15. There are exceptions who stop growing at earlier or later ages. People can also grow abnormally due to endocrine system disorders.
Adult height is partially based on genetics, medical conditions, illnesses, when the child reached puberty and nutrition. Growth occurs in spurts that typically last around two years. Girls begin their growth spurts at 9 or 10, on average. Boys have their growth spurt at 11. Growth spurts cause boys to grow about 4 inches per year and girls about 3 inches per year.
Normal growth, which doctors can determine based on growth charts, is a good indicator of a teenager's overall health. Growth charts can also be used to predict a teenager's adult height. The hormones responsible for growth are growth hormone, thyroxin, androgens and estrogen. The estrogen in the blood increases after puberty is completed, which causes the growth plates to fuse.
Pituitary tumors are the most common cause of endocrine system disorders. These disorders include gigantism, which causes excess growth in the arms and legs, and acromegaly, which causes excess growth in the hands, feet and jaw.