Most people will reach their maximum body height when their puberty ends, but since not everyone experience puberty at the same moment and during the same period, some people may still not get their maximum body height when they reach 20. Growth hormone which produced by the body solely determines on how tall a person will be.
Average
In 2002, Center for Disease Control and Prevention released a data telling about that most male have 5 ft body height and 95 kg body height while women have 81.5 kg and 5 ft 4 inches. This value has increased 12 kg and 1 inch since 1960. Our Guiness Worlds of Records even record that Robert Pershing Wadlow is still the tallest man in the world with 8 ft and 11 inches.
Unstable Percentile
During growth period, there is nothing certain about the percentile. In the first 10%, a baby may become as healthy as someone in 85% percentile, but only if the baby has consistent weight and height development. A growth problem can be seen when the child stopped growing or the growth drastically changes between 1 or 2 years. Another thing that need to be concerned is when a baby gains much body weight without having appropriate body height.
Dwarfism
Until today, there are more than 200 conditions which are different to each other and they closely related to dwarfism with, of course, different symptoms. Basically, there are 2 types of dwarfism: proportionate and disproportionate. When someone suffers disproportionate dwarfism, there are some parts of the body which are small, while other parts still in normal size. This type can limit the bone development which cause an adult may have only 4 ft body height. At the other side, when someone suffers proportionate dwarfism, all parts of his body have the same size and usually people with this type can be found under the 75% percentile on specific charts about standard pediatric growth.
Factors
Other important factors in determining body height is genes and nutrition diet. An example for gene factor: a person with short parents can have tall body height, but his brothers, sisters, or even children in the future may have short body height. Another important factor is nutrition diet which closely related to how good you can keep energy and nutrition balance inside your body. Good nutrition balance is very essential, especially during puberty when body growth meets its gold period.