Use a Punnett Square of a Bb x Bb cross. B is the factor for brown eyes and bis factor for blue eyes. What color eyes do the parents have:

The parents would have brown eyes.

Explanation:

Given Bb x Bb, this tells you that both parents have brown eyes and are carriers for a reccessive trait (blue eyes). Remember that the uppercase letters are considered dominant and the lower case letters are considered recessive. In order for the blue eye allele to show, you would need to have the genotype: bb.