In my family, amongst the guys, I am and have always been the littlest (mostly because I am skinny and the youngest) at just over 6'3". Along with my older brother though, I am one of the taller ones.
On my grandpa's side (my dad's dad), grandpa came along and was a good head, sometimes head and shoulders, taller than the rest of his family, including cousins.
http://i.imgur.com/6qrKcCt.jpg
We have several genetic legacies from Gramp's side. One is height. Another is heart problems. Another is two males are usually born first, then females after. Another is a higher than usual number of twins being born.
Of the kids, the first ones in the birth order, (firstborn son, firstborn daughter) usually take after the father's side in both looks and height. The second (secondborn sons (of which I am) and daughters) take after the mother's side in looks and height.
I have two younger sisters and one older brother.
My older brother is slightly taller than me and nearly twice as wide (he's not fat though, heh), and my eldest younger sister looks like a girl version of him, sorta. He's 6'5"-260lbs, she's 5'9"-138lbs. Both tan really easily. Brown hair that started out auburn, green eyes.
My youngest sis and me look similar dark hair and light blue eyes, can't tan to save our lives (got that from gramps above who was a flaming ginger, haha). I'm 6'3"-170lbs and little sis is 5'11"-135lbs.
On my mom's side, they got big. My grandpa was the shortest at 6'3" and smallest at 210lbs. He had several bros of which I've only ever met one, his next older one. He came in at 6'6" and a full three hundred pounds. He was/is a stone mason and was a beast at mealtime, haha. Total gentle giant though (same with my grandpa) and loved challenging us kids to arm wrestling (five kids against him was about an equal match).
Anyway, it's gonna be hard to tell how tall everyone will get. Knowing your geneology can make a prediction slightly more accurate, but still not 100%, especially give you're trying to use it to predict a final height to within a couple inches/centimeters.
