height is not only genetic, it's a clusterfuck of things, like how the genetype is express, the situation a children grow in, even the diet it's a factors.
i take height expecially because it's has a serious genetic component (when you talk about 'inheritance' you are talking about genetic) but there are innumerable other factors, sarah isn't a mage, but her sister is, and both their parents were mundane (the sariel late husband was a cleric, i think). similar two short parent can have a tall child. (i'm 180cm but both my parents aren't tall, they are in the 155/165 cm range, my sister too)