Question

Two brown-eyed parents have produced three blue-eyed sons. If they have another child, how likely is it that the child will be brown-eyed?

Since all of their children are blue-eyed, there is a 100 percent chance the next will be blue-eyed.

Since blue eyes are dominant in this family, there is a 25 percent chance the next will be brown-eyed.

After having three blue-eyed children, there is a 100 percent chance of having a brown-eyed child.

Both parents have a recessive allele for blue eyes, so it is a 75 percent chance the next will be brown-eyed.