system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How come my twins have blue eyes when both my husband and I have brown eyes.

We have 3 year old twins (non identical) who both have the exact same shade of blue eyes. I have brown eyes and my husband has hazel. Their paternal grandfather has blue eyes, their maternal grandparents have brown eyes. Both my grandmothers had blue eyes. 
I know that the gene for blue eyes is recessive, so I'm curious how they both by-passed all the brown eye dominant genes!
Thanks!
gpt
Genes work like this: we have two sets of genes for everything (only exception is the gender-specific ones), one passed on from the father, one passed on from the mother. Which of the two sets of your parents you inherit is entirely random. 

This simply means that both you and your husband inherited one set of brown-eye-genes and one set of blue-eye-genes from your respective parents and you both passed on the blue-eye-genes to each of your twins. Unlikely, but entirely normal.