Question

If two brown - eyed people have a blue -eyed child, we can deduce which of the following?

Answer 1

There has to be a person in the family with blue eyes to pass on the gene

Answer 2

There are two options to this situation: 

A: the two brown-eyed parents have the recessive gene of blue eyes.
B: the two brown-eyed parents have ancestors that had blue eyes. 

From both the given and the options, we can conclude that the child received the recessive genes from both parents and at least one ancestor had blue eyes in order for the child to have blue eyes also.