Height differences 'could be caused by DNA changes'
Subtle changes in our genetic make-up could help to explain why some people are taller than others, the largest ever study of height has suggested.
About 400 genome regions have been identified that may be responsible for the extra inches, according to research involving more than 250,000 people.
Scientists say this could pave the way for a simple test to reassure parents with fears about their child's growth.
It may also shed more light on cancer, where cell growth is out of control.
Studies suggest up to 80% of what determines height lies in our genetic code.
But the exact genes and other bits of DNA involved are only just being explored.
The first height gene to be identified was discovered in 2007.
But this report, in Nature Genetics, suggests many thousands of genes and other regions of DNA could all play a part.
Scientists from 300 institutions examined the DNA of more than a quarter of a million people across Europe.
And they found 400 regions in people's genomes - their individual DNA libraries - that could contribute to an individual's height.
Researchers say the variations in the genetic material discovered in these locations may have a significant role in how tall a person will eventually become.
"It's common knowledge that people born to tall parents are more likely to be tall themselves," said Prof Tim Frayling of the University of Exeter Medical School, who oversaw the study.
"But I'm surprised how complex the picture is. We have now identified nearly 700 genetic variants that are involved in determining height.
"And this goes a long way to fulfilling scientific curiosity that could have real impact in the treatment of diseases that can be influenced by height, such as osteoporosis or cancer."
Referring to the test to reassure parents that could also be devised, Prof Frayling said: "Most of these children have probably simply inherited a big batch of short genes."
Some of the regions uncovered included genes that are already well known, but others were a complete surprise.
Prof Joel Hirschhorn of Boston Children's Hospital, who was also involved in the study, said: "Many genes we identified are likely to be important regulators of skeletal growth, but were not known to be involved until now.
"Some may also be responsible for unexplained syndromes of abnormal growth in children."