A brown-eyed right-hander marries a blue-eyed right-hander. The first child has blue eyes and is left-handed.

A brown-eyed right-hander marries a blue-eyed right-hander. The first child has blue eyes and is left-handed. What are the genotypes of the parents and what phenotypes can further descendants of this pair have?

Right-handedness is a dominant feature, we will designate “A”, left-handedness is recessive, we will designate “a”. Brown-eyed is a dominant feature, we will designate “C”, blue-eyed – recessive, we will designate “c”.
Since the child turned out to be the owner of both recessive traits with the aass genotype, it means that the parents are heterozygous for right- and left-handedness.

Mother   father

aass   ×    AaCc

Gametes

Aa aa     ss ss

Possible variants of the genotype of children
AaSc brown-eyed right-hander
Aass brown-eyed lefty
aaSc blue-eyed right-hander
aass blue-eyed lefty – first child