I had to chime in on this one!
I have identical, one year old twin girls. Both exclusively breastfed
until I began solids around 8 months. Both still nurse often. The only
dairy they've been exposed to is through me or in baked goods/cooking.
Both eat about the same proportions and have essentially identical
diets. Carlie's hair lies down and "behaves". Kendall's hair stands
straight up all over.
Go figure!