Genetics.

The boys' blonde hair... comes from Kevin. He was blonde until he was 6 or so, then turned brown.
Eli's and Hannah's brown eyes... come from Kevin. Hannah's are dark brown and Eli's are a bright brown, more like Kevin's.
Carter's are more greenish, like mine.
Eli's personality, being a rule-follower and perfectionist... from his mama.
Hannah's more laid-back personality... from her dad.
The boys' fair skin... from their dad.
The boys' eczema... from their mama.
Hannah's golden tan... from her mama.
One of the children who possibly grinds teeth at night... from their dad.

And now Eli who has to get glasses... from his mama.

Thanks, genetics.