Question about height(genetics)

Question

My parents are not very tall, for instance my mom is 5'2'', my dad is 5'4'' and I'm 5'5'' and I'm 19 years old. How is it the my 15 year old brother is 5'9'' and none of my relatives are taller than 5'7''? so my question is where is he getting his height from?

p.s. no he is not adopted lol =)

Answer 1

How tall are all your grandparents?  Since WW2 several populations have grown much taller, 2 inches per generation (the worlds tallest men are the Dutch, average height 6'1").

It is thought that good prenatal care and good care for the first 2 years especially allow people to grow to the genetic maximum height, which obviously is quite a bit taller then what the world believed just 60 years ago.

Incidentally, the countries showing the greatest height gains and average life expectancies all have large nationalized health plans.  The USA has short people and short life spans and high infant mortality when compared to the top 25 most industrialized countries, and is behind some very poor countries too.  This keeps getting into the news regularly but for some reason people in the USA refuse to hear it.