Younger siblings grow more slowly
A University College London study of 14,000 British families showed that on average younger brothers and sisters are shorter than their older siblings.
In a family of four children, the siblings were 2.5cm shorter than average, according to the study. The youngest siblings were worse affected. The reason is unclear but it is presumed likely that parents spend less time, money and attention on younger siblings.
http://news.bbc.co.uk/2/hi/health/6992852.stm
