I've just googled and found this site which shows how to estimate children's height from their parents' heights. It's in the US so uses feet and inches, which is fine for oldies like me
For sons - average of dad's height and (mum's height + 5 inches)
For daughters - average of mum's height and (dad's height minus five inches)
So, eg for anyfucker
5 ft 10 + 5 inches = 6 ft 3
DS would be average of 6ft 3 and 5 ft 11, so you could expect him to be about 6ft 1
5ft 11 - 5 = 5 ft 6
DD would be average of 5ft 6 and 5 ft 10, so she'd only get to about 5ft 8 by this calculation...
But obviously it's only an estimate so if she's already very tall and still growing, then it maybe not that accurate...
I've only got a DS, and his height comes out of this as ((5ft 7 + 5) + 6ft)/2 which is actually 6ft... and his growth chart shows him reaching about 6ft 1.