Height is somewhere between 60-80% determined by a person’s genes. However, consider that environment can potentially play a big part in the outcome of a person's height. Consider that even if a person was predisposed to being tall, if they were malnourished and thus unable to grow at a regular rate as permitted by those genes, they would not reach the height as they would have prescribed.

When genetics are identical, any differences you see must be due to the environment When the environment is identical, then any differences must be due to the genetics

  2. Geneaology