I can see this thread going for a while......
You decide - nature vs. nurture. Mom is 5'2" (she claims 5'3) and very small framed, always has been. Never played a sport in her life but has always been physically fit. Dad is 6' and really should lose some weight ('nuff said). Dad played in high school and was a marginal player at very, very best. Grandfather played at a small college in the 60's and I'm told was a decent pitcher in his day. Two boys. Both 6'3" and a pound or two either side of 215 lbs. One pitches in D1, the other headed to pitch D3 in the fall. One was 93 mph (on a PG gun) in high school, touched 96 as a Freshman in college this year. Second is about 10 - 12 mph less but gaining. Feels like a lot of nurture and not much nature, but who knows for sure.