At what age do current stats/percentiles start to be predictive of future stats/percentiles?
As in, DD is really tall (91st percentile), but DH and I are short. Do we have a shot at her remaining tall? 
BFP #1 9/2010 (lost our baby at 21 weeks)
BFP #2 8/2011 (ectopic pregnancy)
BFP #3 10/2011 (chemical pregnancy)
BFP #4 12/2011 (Abigail born 8/15/12)
BFP #5 5/2013 (Griffin born 1/23/14 with heart defects, now repaired!)
Re: S/O stats
i've also heard this:
For Boys Add 5 inches to Mom's height and average that number with Dad's height.
For Girls Subtract 5 inches from Dad's height, and average that number with Mom's height.
my H and i are short, too- i'm 5'2" and he's 5'7"- so by the method above DS would be 5'7" and any future daughters would average 5'2".