Question

the first child born to two parents with brown eyes has blue eyes. draw a punnett square to show how it is possible for these parents to have a blue eyed child

Answer 1

Both parents have to be heterozygous for the trait (Xx)

X. x

X. XX. Xx

x. Xx. xx

As you can see, in the further corner, there is a homozygous recessive genotype. (xx). This means that 1/4 of all offspring will have blue eyes. Or 25%