I received a question from Karen via our iPhone App and she wondered when you could tell if your child was going to get any taller.  I am often asked to either predict how tall a child will be or to decide if a child is going to grow any more. Growth is obviously very individual but genetics plays a great role. Parents who are both shorter than average typically do not have extremely tall children, and conversely taller parents typically have taller children.  When you have a large family it is not unusual to see some variations in adult heights as the many different genes within the family are expressed.

Typically, girls achieve their adult height about 2 years after the beginning of their first period.  I know that you “hear” many a story of a parent or relative who grew for 6 years after their periods started, and of course nothing is 100%, but typically a girl that starts her period at the “normal” age of 12.5 years will have achieved her adult height by the age of 14 – 15.

Think about middle school, where the girls are typically taller than the boys. If a girl starts her period earlier, she will not have as lengthy a growth period and may not be as tall as was expected. With that being said, a teenage girl who is only 5 feet tall at 14 years of age, and is thought to be short, but has just entered puberty and has not started her periods, has a longer growth potential and will actually be taller than expected by the “norms”.

It is easiest to predict a girl’s height once she has started to have some pubertal changes with breast development etc.  Once their periods, have started most girls will grow about 2 – 2 ½ inches over the next 2 years and will have achieved their adult height at that time.

Boys are a little different and have a later growth spurt than girls.  Most boys enter into puberty between 12 – 17 years of age. Again, there is wide variability.  Boys like girls will have about a two to three year rapid growth period, where there may be as much growth as 4 inches in a year.   Boys will usually grow during their high school years where they typically surpass the girls who had an earlier growth spurt.  Many boys, especially those that have later pubertal development will grow throughout high school and occasionally may return from college with another inch or two of growth.

That's your daily dose. We'll chat again tomorrow.